Not really, kinda like when graal facebook came out, no real noticable increase. Mainly the people playing on Android are people who already played Graal in the first place.
Until they put it on google play, I doubt we'll see many new players. I imagine he might be putting it just on amazon first as a form of large scale testing, so that the app has a good impression to new users(which is good, AFAIK the android client had a few issues at release)
Or, it might be that the whole business model he's using doesn't work with google play(he said something about that a while back)