To further clarify, Keybase Sites based hosting should still work as far as I understand. I don't use keybase.pub and I'm a hardcore Keybase user, so I imagine most don't. You can still get hosting through Keybase Sites.

EDIT: No, I'm probably wrong.

https://book.keybase.io/sites

Are you sure about that? It's under the keybase.pub domain name according to the docs you linked. I would have thought that means it's going as well.

I'm not sure, and under further investigation you might be right.