Wow there's a surprising amount of negativity here.

I've used this for a fairly complex app at work and it's great. (It's certainly not vibe coded as one commenter suggested.) It's a Python layer on top of Flutter, and it was the only UI framework I could find for Python that was fast and worked on all major desktop and mobile OSs. I think maybe Kivy could too but it seemed like it would be an uphill struggle for a good desktop app.

It's a bit of a gateway drug for pure Flutter. If you need some complex, quickly updating control then you can write a Flutter control (in Dart) and wrap it in a Flet (for Python) control for better performance than doing it all in Python. I've ended up doing that for the main display in our app, and there's always the option to move more and more business logic into that.

One downside to Flet is that I wish they didn't try "fix" some design decisions in Flutter. For example, they have a Flet "Container" widget that wraps a bunch of different Flutter layout widgets. The Flet version does seem easier to understand to me, but there's just so much more documentation (and StackOverflow answers etc.) for Flutter than for Flet that it would be easier overall if they just mirrored the Flutter controls precisely.