So, does this mean we will use pkarr keys as our identity and source of truth and nostr npub will just be a record entry that we can change and in a way be able to rotate? clients will use pkarr key to look for the nostr npub that you actually follow, and if it knows the old npub and the new npub and when it changed (this might be tricky prob.) the client could show you the notes of the person you follow in a seamless way without you ever knowing that he changed npub along the way. Could this all be done using only nostr? probably but i think it would be a bit more complex. Don't know i am bit retarded on this may this doesn't make any sense. 

 Really it just needs a transition operation and for a while maybe a dual signed extra tag 

 I didnt think of this.  But yes, that is very smart.  I would not say *will* use it that way.  More *could* use it that way.  Nice thinking!