I wrote myself an app that was very useful to me personally. I knew zero others who might be interested but was able to publish it. At its peek there were 100 users. It was relevant for just under two years and is now gone. That was super successful and useful for the people who used it. I would have had no way to get it to anyone but me had this policy been in place.
Edit: I don't even know 20 Android users. Maybe 5. Everyone uses iPhones.