What an odd scene this must be. Snoke Force Pulls the lightsaber from Kylo, then Pulls Rey up onto his platform as well. Snoke doesn't even bother looking at the lightsaber either. It's like he's trying to be intimidating (which he sort of is), but badly needs glasses to actually see Rey.

As snarky as Pete is, turning evil does seem to be the most likely reason Rey is here. There's the Kylo conversations and the slime pit visions, plus the bit where Luke got really worried about the rock breaking apart. The only alternative I can think of would be that the writers wanted Rey to meet Snoke in this movie, so they gave her a massive Idiot Ball in order to get her to come visit. I would hope that Disney could hire better writers than that, but I have also heard now that the movie was not enjoyed nearly as much as Episode VII, so this could be part of that dislike.

Also interesting to note is that Kylo seemed to not get weird visions either. Perhaps the visions are due to the relationship to Luke/Anakin? Assuming there's been nothing changed, that'd leave Leia as the only other person directly related who could get the visions. Of course, it could just be that Rey has the Main Protagonist skill of vision seeing, but where's the fun in assuming something like that?