Not necessarily. Discord is a pretty popular platform for exclusive access to selected people, e.g. Patreon supporters. As long as OF allows this kind of link it might stay relevant.
Except they have the reputation of porn, but now they don't have the porn. I wouldn't go sign up for an OnlyFans account in order to follow a SFW creator, simply because the reputation OnlyFans has. However I would join their Discord or Patreon.
Now their in this weird uncanny valley of "adult content" combined with "no adult content". Seems hard to shake that image.
Did you know Pornhub has a social network-like function and achievements? But if a coworker wanted to connect with you by asking you to add them on PornHub, you'd probably not think that this is about a casual coworker friendship.
It's going to be similar if people link to OnlyFans instead of Patreon (or Locals).
Patreon already exists for exclusive SFW content, and with exclusive Discords you can also interact with other fans of the same content. Not sure where OnlyFans would fit in other than "different Patreon".