The difference is that on nostr you can have immediate interactions with others, you can get their comments, you can message with them, etc.

In your example you can think about nostr as a protocol on top of "your own websites" that allows all people with "your own website" to effectively communicate and live interact with each other. And creating "your own website" is just a matter of clicking a button in any nostr app that generates private key and public key pair.