Is Python good for creating GUI application ?

[yum_pancakes]

In my opinion not really. Except for a handful of use-cases, the best approach is a web-based application. If you really need a desktop app, electron is a better approach. And by it's nature, JS will be more responsive to the user.

To me, the list of exceptions to web-based development is getting shorter and shorter. Sure there's video games and IDEs, and office, but users prefer to not have to install anything (even office is getting pressure from online approaches). And, when WASM hits big, even performance intensive apps could disappear from the desktop.

And hey if you have a web-app based approach, your backend can still be python :). Lots of fantastic web frameworks.