I think a dedicated "TikTok but AI" is infinitely better than AI videos polluting other platforms. Of course, in practice, the latter is already the case, rendering the theoretical benefits of the former kind of moot.
Nonetheless, a platform for AI videos with an audience looking for them, rather than the horrible "boomer-slop" that is prevalent on other social media, is welcome in my eyes.
I think a dedicated "TikTok but AI" is infinitely better than AI videos polluting other platforms.
They'll just cross-post. That's been going on since back when Facebook was The Face Book.
I don't think this is going to reduce the slop on other sites at all though.