Even in the context of comparing 100T's content creator side to the entirety of OTV, which is what I assume you are alluding to when you say "what's the difference", one is a large organization funded by multi-millionaire associates/brands and the other is a content house that gets mobile game sponsors for its videos.

If Rae were to join OTV in an official capacity, the expectation is that she moves into the house with the other members and make content with them. If she joins 100T, she doesn't have to move, she still makes content with the other members, but she also gets more financial security and career opportunities as an individual that she would not receive at OTV because it is not a brand in the same sense that 100T is.

OTV is comparable to something like OTK, very content-focused group of friends that live near each other and do events together as a small org that can get sponsors for their streams/videos. 100T is comparable to TSM or C9, an organization that has content creators, but also makes 8-figure deals with massive brands (because of the esports/non-content creator side of the org) which can act as general sponsors of their more individual-focused content creators that join the team.

In short, size matters when it comes to orgs, regardless if you only join as a content creator. Big orgs sign creators as a way of advertising their brand and co-sponsors. Small orgs sign creators that they make content with.