Why Nostr Login?

The answer would depend on your definition of a 'nostr app', let's assume you mean 'why use login with Nostr if you're not building a micro-blogging social media app?'.

If you need some identity system in your app, you generally have two options: - build your own system, ask users for email and password, etc - use big centralized providers like Google/Facebook/Github, etc.

With Nostr you have another option, decentralized and built on cryptographic keys, not a closed centralized database with emails and passwords.

If users login with Nostr you can fetch their profile, their following list, their other public data, to personalize the experience in your app, to train your AIs, etc.

If you app has important 'social' component, then you might have an easier start with Nostr where people already have some social graph.

And you can use Nostr for some social parts (comments, reviews, etc) and use your traditional app backend for the rest of it.

Nostr usage in your app is not all or nothing, it's a wide spectrum.