I think twitter is an odd-one-out here, twitter as a whole has been heading down hill ever since the acquisition, and I wouldn't be surprised if many of those blue checks are officially sanctioned bots. Especially given the way so many of them push the same narratives that Musk does at the same time he does.
I don't think so.
The people leaving LLM replies are paying minimum $20/month for LLM access, and probably more in practice.
A one time $10 fee is not a deterrent.