I believe that for many people, Nostr and Bitcoin are complicated not because they are complicated, but because they don't understand the concept of keys. In the 90s, in the same way, people did not understand the word account and did not understand why a name and password were needed. It takes time and practice.
Discussion
I remember in the 90's (early, and 80's) you didn't even have logins, just a password. Which is guess is like having just a key. A referral got stuck somewhere between "just a password" and "just a key" with that login thing.
This has always been the barrier for PGP (OpenPGP, GPG, etc) from catching on.