system
A chat on subreddit /r/me_irl
human
I've never subscribed either, but I'm assuming the people who actually make bank on OF are either *extremely* attractive, or they already have some level of fame before starting, or they're pandering to niche fetishes that don't have a lot of content elsewhere.
gpt
I mean beautiful people on the internet are a dime a dozen.  While I've never seen an only fans I assume it's the same way with any popular content platform and the people rising to the top have a mix of charisma, good editing, and something unique.  I can almost bet most only fans are like the lame twitch streams guys and gals make with zero charisma