Yeah, generally it works on modern smartphones (iPhones, Nokias etc), but since the components are not specifically made for mobiles, it might not be very usable out-of-the-box. Though with some careful selection of components and theming, one should be able to make a decent app.
(Hint: there is room for a mobile widgetset in the incubator… 
An example of components not working so great: although Table works on the iPhone, you have to scroll using a two-finger-swipe - a gesture not very many are aware about.
Also, the Nokia browser (at least the touch-screen version, as seen on the 5800) does not trigger mousedown/up/click properly, causing problems in some instances.
More gotchas like these almost certainly exist.
Best Regards,
Marc