We're working on a cross platform mobile app rn and we're using QT because "everyone else in the company is using it". It might be good for desktop, but I've found it to be nothing less than frustrating, it reinvents the wheel for mobile, and doesn't do it very well. It's still missing many features, we still have to keep going back to native views to implement things because QT just can't do certain things. We've lost developers because they want to work with mobile technologies and QT seems like 10 steps back. Swift and Kotlin address many issues of cpp, we don't have access to the wide amount of mobile libraries. We replace things with cpp libraries never compiled for ARM that ends up with incredible amounts of code that would take a few lines in native. Every library we add brings more headaches. And then we have desktop developers diving in and designing everything like it's desktop, button and menus too small, scaling the view to fit different device sizes. ugh

Yes I am aware of the alternatives. Still having used a ton of UI libraries (Unity/Unreal/Godot/C#/QtWidgets/Flutter and web development) I would still choose QML by a landslide. My project ScreenPlay [1] (Cross plattform animated wallpaper and desktop widgets) is written 100% in QML and C++. I use the build in Material Design on desktop which works really nice with fancy animations. At work I develop a cross platform Qt app for desktop and Android tablets. With QtCreator 4.11 they unified the apk creation for all arch and arm versions.

[1] https://gitlab.com/kelteseth/ScreenPlay