Well it definitely didn't pay off for me, yet. But I make regional German card games, so it may vary for you. I don't remember the certificate to be 500$, though. More around 100$. Maybe they changed it or you are looking at the wrong one?
Some numbers:
ARPU for Android is 2.5 times higher than for Windows store (Keep in mind the payflow on Google Play is much better than in your own Desktop app)
Daily Installs are significantly (more than 20 times) higher on Android than on Windows store
Hope that helps.
Best,
Ruben