I list my apps on alternative app stores on Android. It's nice for incremental revenue. What a lot of people in Americanized western markets don't realize is there's many areas of the world with very low credit card penetration and effectively no way to buy things on Google Play as a result. They might pay for things digitally using weird digital currencies you've never heard of (like Razer Gold in Singapore) or via being billed directly by their cellular carrier and using the credit they have on their account as if it were a debit card (kinda like how things used to be before the App Store when you wanted to buy some J2ME game or ringtone via your carrier's content portal).I’m curious to hear from app developers in the future that use alternative app stores. Competition usually drives the prices down, but that doesn’t mean developers end up with more revenue…
There's a bunch of different companies out there that help you get on these different app stores at little or no cost, and then anything you make from your app from this app store is just kinda gravy on top of what you were already making on the App Store or Google Play. For some developers this can be a significant revenue channel, for others it's a random check for a couple hundred bucks that you wouldn't have had otherwise.