Yes, a girl doing OnlyFans is making money.
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.
With Tiktok, Youtube and the like, the comparison gets even worse when you compare the abyss of money making vs. value produced..