In my experience:

- Qt Widgets worked fine, but looked like a piece of software made in 2013;

- QML looks stylish and is a very nice language, but had a lot of weird bugs.

Neither of these are issues I'd run with if I were to make a web app.

> - Qt Widgets worked fine, but looked like a piece of software made in 2013;

That's too bad, because I prefer software which looks like it was made in 1999.

Widgets looks like whatever you want them to look like, if the feel like they're from the 2010s its because the implementer made that choice, not because of a limitation in qtwidgets.

Could be, but I am mostly speaking about the fact that making a web app looks stylish feels infinitely easier to me.