Why would Sidious want a dyad with Vader?

In the ROS novel it is stated that Sidious had tried and failed to create a force dyad with Vader.

But my question is- why would Sidious even be interested in doing that? Dyad seem to revolve around almost sharing power (that's why Rey was basically able to upload all of Kylo's knowledge and skill into herself during TFA, that's why they were able to communicate over great distances, and even pass matter back and forth), so why would Sidious want to share an ability like that with his apprentice?

Because that would make him more powerful I guess. But the real answer is bad writting. Best to ignore that novel.

There's also probably a lot more to the dyad then the few things that Rey and Kylo subconsciously displayed. Abilities that Sidious could have exploited for his own means.

True.

Like don't some sources mention that force healing was an ability unique to dyad users? I imagine that ability in particular would have come in handy for Sidious. 😛

Baby Yoda used force healing, so no, it's not unique to dyad.

Yeah, Force-healing obviously isn't unique to dyad users, but it is implied that the reason Rey and Ben could use the ability was because of dyad mumbojumbo.

I still think this whole Dyad thing is contrived and not needed.

Agree.

Take the dyad concept out of the movies, and nothing changes.

It was needed to justify why Rey didnt need training to do advanced force shit.

Honestly I think JJ just didnt get how the force works (ironic given Han Solos line in the film), so he probably originally thought that didnt need explaining when making TFA.

You disgust me. You check on Mouse content.