Maybe it's because some girls are against porn fakes and others are affraid their accounts will get suspended (they will, because websites hate deepfake porn and the same applies to liveshow websites like chaturbate). Unless you mean like regular live streams, in that case I think it just takes some thought to come up with an idea for live stream where face swapping celebs would make sense, I mean if I'm watching some random person playing video games I don't really have the need for them to turn into Margot Robbie of all people, maybe if it's a streamer that does voice overs and can do impressions they might fire up DFLive for a while to face swap themselves into some celeb but that would be it.
The issue is there aren't many RTM models around and 99% of potential DFLive users don't know how to use DFL in the first place to make them.
I think it would be cool to set up like a marketplace for RTM models where people can commission RTM models for donations.