Those "basic form controls" are a bit of a red herring. QML is so insanely great because it's so easy to use the same (C++) core and have a small, easy to code and smooth gui on top of that that nicely fits in with the platform.
I mean... Look at Calligra. There are at least five gui's on top of that: the desktop QWidget one, the Harmattan libmeegotouch one and three QML-based gui's: one for meego, one for Plasma Active and then there's Krita Sketch for Windows 8.
QML is awesome, and the more platforms include it, the happier I'll be.