I mantain that it's not useful, we have web preview which is the best thing ever and works on the actual device, also construct2 is closed (apart from plugins) so it's not like having an environment like mobione will do any good (develop on c2->export->load mobione->test) too much work and still doesn't address the only real problem that we have which is speed for games.
All these "frameworks" that are popping out like mushrooms are more of the same and address problem that are not important, I bought a used macmini for development for 200Euros which is not too steep to have an actual way to test on the real device.
So far I've only seen Ashley trying to address the real problem of html5 on mobile which is the lack of webGL, I don't know how many of you are aware of this but he actually made an effort to create a plugin for phonegapgap to implement webGL.
I developed a game for iPhone which is sitting on my hard disk waiting for a better compatibility with appmobi and direct canvas since I can't get stable fps right now, I tested everything in construct2 developer mode and web preview, and I'm using advanced features like the accelerometer (that works perfectly) and all the other features you can access with js. In my opinion there is really NO need for a fake simulator since with c2 you can preview on the actual device.
Again I've not actually anything against mobione, I just can't see the need for it.