I hear the same pitch, over and over: I have this widget. It lets you write <insert high level language that everyone already knows here> and it spits out <insert lower level language and its UI toolkit here>! It saves so much time and it’s easy and it lowers time to market and and and you can even write Java! There’s ALWAYS Java going on with these things, for some reason. NO! Bad idea.
Well, let me be clear about it. The idea itself isn’t so bad; it’s the HORRIBLE implementation that almost always comes along for the ride. There are exceptions, of course, but I contend they’re the minority.
There is generally some huge functional void since someone has to implement classes to fill functionality gaps where there isn’t a reasonable mapping between libraries of the two languages and they never quite finish. This makes using the widget not quite as good as learning the output language, not to mention having to learn the widget’s libraries, which are supposed to mimic the output language’s libraries (and they often don’t). Then, there are bugs. Lots and lots of bugs to terrify you and give you nightmares. Why not just spend a few days learning the language you need to use? Your engineering skills will get you through it.