I use it for my projects (and one project even makes enough revenue that I sponsor Sebastián’s work through GitHub sponsors at $250/mo) and it for sure has increased my development velocity.
It’s an absolute joy to work with. The automated interactive docs are great for iteration. Type hints as first class citizens is an awesome developer experience that I didn’t think I wanted.
Using the auto generated OpenAPI you can even generate client side code and typings to interact with your API.
It feels like flask but with lots of quality of life improvements.