I use it to generate and play with interface layouts, then run the .ui file through pyuic5 to convert the interface into Python code. I've got a number of Raspberry Pi touchscreen projects that this has worked well for - I can develop on my Mac, and use the same interface on the Pi's touchscreen.

A lot of the people not doing web dev. It's a pretty good cross-platform toolkit, both for traditionally looking desktop apps and stuff that's custom design-wise (esp using QML for the latter), and free as long as you can live with an LGPL-dependency.

(Asking less condescendingly might help against downvotes)

Yes, people use it. It's awesome and so is qml. Many multiplatform software use qt. Then there is Linux and kde and all that.

Please learn to leave your bubble once in a while. It is the only way you can develop.

There's a world outside web dev, you know! I have used Qt in many companies (some examples: forming a major part of the UI for a unified comms client, UI for screen/interfaces for an embedded system, desktop app for analysing/processing finance stuff).