You're picking up on an element I think many haven't quite grasped. Nostr is using cryptographic key pairs for identity creation & management.
It's completely permissionless but it comes with zero cost to the key creator. In order to be heard amongst the noise that comes with zero cost communication, you need to demonstrate PoW.
This is more than just a Twitter replacement. This is the start of humans scaling trust in cyber space. It's really hard for me to articulate why that's important, but I feel it deep within.
We still need improvements to private key management & identity transfer but that will come.