That depends on your screen size! But of course I would never use QWidgets on mobile, with the only exception of direct painting (using a QPainter on a plain QWidget).

QML is easier anyway, and gets better with every version...

Not all Qt developers are happy to be forced to use QML, which again, was my point to start with.

C++ Widgets should be able to offer a mobile friendly version of themselves.

Which was actually a point that was discussed for the Qt roadmap at Qt World Summit 2017.

OK, I understand your point. Good luck, then!

Thanks, but actually I don't use Qt anymore, that bug and a few other ones in 5.4 lead me to use Java and C++/CX for the UI, with common business logic in C++, in a MVVM approach.

The approach of re-doing in QML standard UI components is not appealing.