Earlier quoted context omitted.
Yes, a girl doing OnlyFans is making money.
Turning that into a career seems like a moonshot, making it comparable to other "achieve celebrity" plans young adults may have (become a movie star, become a famous youtuber, become a famous rockstar, etc) I think in general these aspirations shouldn't be shat on, but young adults with these aspirations should probably be gently guided in more realistic directions.
I've noticed that many of these girls are college students and the money from their admirers is useful to buy clothes, gadgets and to take their boyfriends to fancy vacations.
So as long as you are aware this is a bubble you will be doing fine.