The show has been on long enough that various plot holes begin to creep up. Like in the first season demons did not have to smoke into and out of bodies, it was just one way to possess. Normal demons took over bodies via touch as well. Then when they encountered that first demon on the airplane it had the whole thing of getting stronger if removed from the body and turning into some larger black cloud then it was already. I guess it's like the "Vampire Diaries" where early in the series Damon could fly and conjure smoke and ravens.
That is the first season, so it might be excusable, but now we have Amara, who feeds on souls, feeding on demons. Yet during the whole thing in season 7 with Kevin and the tablet it was pointed out Crowley doesn't have a soul due to being a demon. He tried to sell his soul to the God of Greed.
Also with the cuffs maybe they had symbols carved on them to lock the demon in? Like they have on their trunk. They also have an out for why Sam can do this even though they don't use it: demon blood. Sam doesn't need to drink it to get powers from it. It's what made him immune to Croatoan. They could at least say it gave him some small level of supernatural strength left over from all the demon blood he did chug in the past. His demon blood is also how I originally thought he'd beat the Darkness infection.
I guess it could be the shows way of showing Sam is the more skilled hunter, which I guess technically he is on a purely physical level. Which okay hunting comes down to physicality, knowledge, and instinct so I guess you could say Sam overall is the better hunter.
I kind of missed the YED, he was cool. He had a way about him...and he could do crazy shit like possess reapers.