Where’s that used? And what for?

Good.

To follow people privately..

Yes. The next version of Amethyst is looking to make steps in the right direction for user lists, private following included.

But why? I don’t really see the point yet.

I dont want to tell the world who i am following.

Is there a NIP for that?

Probably Ryan knows better, but you can just store it in device storage.

Why not? The lists nip has private and public options already. This just exposes the feature to be used. Maybe someone wants to follow people but not advertise it. Say their family list for instance, or a team working on a project that is under wraps. Maybe you want to follow a bunch of porn accounts and not look like a gooner. There's lots of possible reasons. Same for mutes. Amethyst & Jumble have private mute lists, a feature I appreciate.

Nip 51