In theory yes, you can mention your nostr key in your pkarr records and login with that... sort of adhoc delegation but in practice that is not good idea.

Unless you mean only using pkarr to identify apps and server, not users.

You have seen how I designed Login with Pkarr in Pubky. The downside of that is that there isn't a mature ecosystem of pubky homeservers for apps to be built against yet. And if we want these homeservers to be as good as Proton Drive (Peergos) then there is even more work to do and headwinds for adoption.

I also don't work on Pubky anymore so I can't promise what is going to happen there, and I can't promise I have the energy to build the full solution and rally people behind it in my free time.

So I don't blame people developing against nostr relays and Blossom servers as imperfect as they are.... but I wonder, why not wedav or remotestorage.io ... that shit is mature enough.

Anyways, I like what you are trying to do, as hard and unlikely to gain much traction as it is... it is an idealistic work and I salute it even if I don't agree with some of your assumptions.