"HTML is fast to develop relative to native apps"

I know how to write HTML as well as Android XML or Dalvik (Java) code. I do not see where pounding out HTML code is faster than say pounding out Android XML code.

The only thing fast about it is theoretically you can use it on both Android and iOS. Most companies go native. Facebook tried doing this before running into massive problems and going native.

I also do not see what the frequency of app usage has to do with anything. I might have two app ideas - one used once a month by 60 million people, another used daily by 2 million people. If they are ad based, they will both probably bring in the same amount of money. Why should I go native on the 2 million app but not the 60 million app?