if Ur reading this please don't use nostr for Ur secret dm's, just use signal or simplex instead. nostr is meant to be a public protocol and if u read the nip you will see a bunch of shortcomings/compromises just to force DMS on nostr, which it isn't meant for 

 Or just use the new DM system in Nostr, which uses this new encryption. :) 

What the NIP says is that the encryption on itself is not alone a good chat spec. But people can build really good ones on top of it.