My point is that question is sort of a category error. It's like asking what type of business the internet is for, or what the use case of smart phones is.

Here are a few things built on nostr, with specific use cases:

primal.net is a twitter-like client with bitcoin micropayments and long-form articles (also see coracle.social, nosotros.app, jumble.social, Amethyst, Damus, yakihonne.com and many others); zap.stream is a twitch-like client for live streaming; flotilla.social and chachi.chat are group chat clients; dtan.xyz is a client for torrenting on nostr; satlantis.io is sort of a travel ratings thing; zap.cooking is a recipe website; yakbak.app is for voice messages; nutstash.app is a cashu wallet built on nostr; cashumints.space lists cashu mints that advertise themselves on nostr.

What's neat is that all these clients can do things the way they want to, but remain interoperable, which means that new developers can create an app and immediately have access to all existing nostr users and their social graph.

"nostr is a simple distributed protocol to build internet applications for social networking, communication and media.

It requires lightweight relay servers, as opposed to large federated servers like in mastodon or email, or fully p2p like scuttlebutt.

It can be used to some extent via a browser using web clients, but it's best used alongside extensions for authentication and key management"

That is what I'm looking for. I'm not sure it's a good description, but I wish something like this was front and center

The question isnt a category error and deserves a direct answer.

If I follow what you're saying the answer could have been: "it's a framework/set of protocols for building a Twitter that can show all the stuff on other compatible Google+/Facebooks"