I have seen several posts here about cocos2d-android, so ambition to get more idea on it drag me at coco2ds-android-1 and a good example .
My analysis can not find any significant benefit of using coco2ds instead of usual 2d approach of surfaceView and SurfaceHolder.Callback .
I will be thankful if anybody have expertise over coco2ds-android will guide me about benefits to use it instead of usual gaming approach .
Just by clicking on links starting from the ones in OP, I have came across http://dan.clarke.name/2011/04/how-to-make-a-simple-android-game-with-cocos2d/ - which states the obvious answer you are looking for.
First of all, this is a 2D gaming engine. All of the physics and whatnot effects are just there for you. No need to re-implement from scratch
Secondly, this is actually a port of the iPhone gaming library with the same name - great news if you also plan on porting to iPhone. And thirdly it is open sourced, meaning you can tweak anything accordingly.
I have noticed however that this is a pure java library, so do not expect amazing performance. If performance is critical, google for something NDK based, not SDK based. I could not advise here as gaming is not my thing.