pipe on Nostr: Sort of. The innovation is not in having a key. The innovation is having a universal ...

Sort of.
The innovation is not in having a key.
The innovation is having a universal key and using that key in lots of different contexts, but anonymously and leaving the user the ability to have mutiple keys, share their keys, or change keys at any time.

So, any system that needs to know who it is interacting with, can use it.