That is kinda how Nostr is meant to work. But there’s an open debate in the dev community about how much to put in relays (just text? Images? Videos?) it’s still an outstanding question.

If relays house too much data it’ll be hard for people to run small relays so the network will be more centralised. If relays don’t allow people to store whole files in them, then those files will have to be stored somewhere.

Personally I’d like to keep big files off relays and lets solutions like Nostr.build provide specialised efficient offerings and accept Bitcoin as payment.

But there’s already apps that allow a Nostr user to create notes and store them on relays.