1. Network effects are baked-in. Devs don't like to sell/advertise. It's nice when you can just create something and use an efficient social design to let word-of-mouth do its thing without relying on a controlling party, like an app store. It's also incredibly rewarding.

2. Database is solved. Users will choose their relays. You don't need to put anything up. There is no need to spend hours specing out your database tables, mapping them into objects, and then making all the data access layers. No liabilities, no operational costs, no risks, and, more importantly, no long-term commitment to secure and keep the data available to your users.

3. Login is solved. Devs generally start any app with the Account Management part, designing screens, o-auth backend, password recovery, 2-step auth and so on. It takes a lot of effort to get to the point where you can actually build the app you want to build.

4. Social First. Every app is a social app. But devs usually build things first and then add a social "feature" into it. That doesn't work. With Nostr, you are forced to start with the social component and build what you want to build on top of it. And devs see that as an extra positive feedback loop for the community.

5. Do whatever you want. It's shocking how open Nostr's data models are to any type of application. Just pick a number, sign, and go. Make a NIP if you want to interoperate with others.