No, because "just a battle of wills" would be a telepathic battle. It's like Yoda said:
“My ally is the Force, and a powerful ally it is. Life creates it, makes it grow. Its energy surrounds us, binds us. Luminous beings are we, not this crude matter."
Hence:
"You cannot touch what is not real. Your cybernetic hand is just illusion, as much a shadow as flesh and bone." Ryontarr reached out to tap Luke's chest. "That is real.""What, exactly, is real?" Luke asked. "My spirit?"
"Your Force presence. It's your true self, a swirl in the living Force that animates your physical body." Ryontarr tapped Luke's chest again. "This is what truly exists." He pointed over Luke's shoulder. "It gives form to that."
"That being my body," Luke clarified.
It's why when one becomes "One with the Force" their body just disappears. Their Essence gives their body form to begin with. This is clarified here:
Luke looked back to his body. "Then my body is more substantial than my clothes because... ?""It's not."Ryontarr pointed at it. "Touch it."
Luke obeyed-or tried to. When he pressed his hand to the body's face, it simply sank through the cheek. The body's eyes widened in momentary alarm, but immediately grew vacant and glassy again.
"You haven't abandoned your shadow body yet," Ryontarr said. "There's still a tiny part of you inside, because you aren't ready to give it up entirely."
"And that part is giving it form," Luke surmised.
Finally:
Luke rose out of his body with a jolt, then hung floating above it, staring at the underside of the bunk above. A week passed, or maybe it was a second-he had no idea. Time had no existence outside the body. A heartbeat lasted a week, a lifetime flashed by in an instant. But Luke Skywalker remained, a manifestation of Force essence that embodied mind and form, more real than the material husk he had left strapped in the bunk below.He exhaled, or imagined himself exhaling, and his connection to his body grew more tenuous. There is no life, there is only the Force. It was the code of the Mind Walkers, an assertion that the corporeal was illusion, that a living being was nothing but a luminous swirl in the Force. And perhaps they were right.
Luke exhaled again, and a purple radiance appeared above, shining down through the crude matter of the upper bunk as though it were a hologram. He reached, and the light came flooding in, filling him with a calm as deep as space. He became the Force, and the Force became him, and he knew only the pure, eternal joy of existence.
So actually, the fight was not less real than a physical battle - it was more real than a physical battle.
Here's another way to look at it.
The body is a vessel for the spirit. The spirit lives inside the body. As the body grows, the spirit grows. The spirit gives life to the body and allows it to grow, and in response, the spirit takes the form of the body and grows alongside it.
Unlike raw Force energy, which is just blank and devoid of any intelligence or individuality, the spirit has a personality. This personality develops because a human being lives in the physical world, grows, has new experiences, and so on.
The spirit can only be as great as it's vessel. The spirit of a rancor will never become great or do great things because it only has the potential of a rancor. Ki-Adi-Mundi will never be as great as Mace Windu. Luke Skywalker will never be as great as Abeloth.
What happened with Beyond Shadows is sort of like creating "another body", but not quite. Try thinking about it like water and a glass. The body is the glass, the spirit is the water. Without the glass, the water will just spill everywhere. You can't do anything with the water, you can't add or take away from it. There's nothing unique about it.
What Krayt and Luke did is they filled up their glass of water over the course of their life. When they went Beyond Shadows, they poured the water out of their glass, but instead of spilling everywhere, it maintained it's shape. The water retained it's individual form despite being separated from it's glass. This is because the spirit has a will, an intelligence, that can separate itself from the Force. Luke and Krayt retained their identities.
And the reason they were able to pour their water back into the glass, or place their spirits back in their body, was because they left a small part of themselves, a "vestige" inside their bodies. The maintained a connection, and using that connection they were able to go back. It was also because of that connection that Luke's physical body had a hole in it's chest after he went back to it.
Force Ghosts aren't really connected to the Living Force much, if at all compared to a Sith Spirit, who are tethered to it directly in order to stay alive. And Krayt and Luke were obviously different from either in a few important respects.
Anyway, not really seeing your point other than personal incredulity.
If they were just Ghosts, they would be in the Depths of Eternity with all of the dead, like Mara and Jacen. They are living beings who have separated from their bodies in a realm that is comprised of pure Force energy. The same power they were comprised of there is the power that gives their bodies form in the physical world.
It's not rocket science.
Obi wan could not interract with the living world.
Force ghosts are just the souls of living things. The force is made of the souls of living things, and the real world is completely separate from that. Some things, midi-chlorians, lightsaber crystals, and certain pieces of technology, can access the realm of the Force and remain in the physical world, thus manipulating the physical world using the energy created by the souls of all living things (The Force)
Now, Obi-Wan did sit on a log, but I don't think he was actually sitting on the log. He no longer had a phyisical presence. The only way he talked to others was by talking to their souls, which exist in the realm of the force. The physical form that we see in the movies is just a representation. He wasn't actually there.
And what Luke and Krayt did is different from being one with the force. To be one with the force is to be one without physicality. Luke and Krayt had their physical forms, they just weren't inside them at that moment.
And ILS. I don't know what you mean about spirits being superior. I don't think any spirit is superior to another. If they're all completely with the Force, then they're about as powerful as anyone can be. They can't manipulate the real world like the The Father, but as far as their connections to the Force goes, they're just as powerful as the Father. Though not as effective.