Of course for mobile games. Crosswalk is exactly that. A browser engine wrapped into your APK to play back your html5/JS-game. That's what the whole thing is about.
The different sizes between Crosswalk and cocoonJS come from the different implementations (CocoonJS has a lot less features and overhead than a full browser engine). But you will never have like: a 1mb APK, because one way or the other: there needs to be a rendering engine packed into it.
That's the fundamental difference between APKs from a HTML5-engine like Construct2 and a natively developed Android-game.