So in the case of LNBits, NIP-98 is used to auth with nostr, Is that what you mean by centralized server.

Since there is an LNBits API for NIP98 login (afaik) , it means that any nostr client, can auth to lnbits ..... so if this is not the correct interpretation, let me know 

 I was trying to "let you know", but I'm just getting rudeness in response, so I will stop for now. 

 😂 its just been a wet, rainy day. don't take it personally