I noticed about a couple developers using QT to build Android apps, but none for iOS.
Well, I develop an QML app for android and iOS, for example. Currently it is in TestFlight stage, the android version is already released. I use an individual GUI though. QtQuick Controls (or also QWidgets?) can mimic the android KitKat style, but there is only a very experimental lollipop "material" style yet .
I find it worse if an app has an GUI which tries to look&feel native, but is only reaching 85% at being native than and app which has an individual GUI. If you want to look&feel native, you have to go native on mobile. That's the deal IMO.