I have, but I'd rather stick to one set of proprietary technologies (the app platforms themselves) than learn another proprietary layer atop said first proprietary layer, and risk constantly scratching my head in vain when inevitably the abstraction leaks and things become inconsistent.

Not to mention lock-in. I'm already at the mercy of the respective distribution channels - I don't need to add to that pain.

Edit:

Don't get me wrong, I'm happy that these things exist. I like anything that lowers the barrier of entry for people who otherwise wouldn't write software. It's just that you're trading a lot of maintenance/optimization time for a shallower learning curve - and it's important to make that known.

Also one last point - the reason why this kind of stuff typically needs to be learned through painful iterative experience is because it's typically undocumented. In most cases it's undocumented specifically because it's not a supported development path, and as a result it's very likely the techniques you discover today will break tomorrow.

It's a lot like leveraging unspecified/implementation-specific language behaviors in C.