I run the Amazon App Store and Humble Bundle on my Galaxy S4, both of which are APK files I side installed and I have many apps from both installed. I don't thi

I run the Amazon App Store and Humble Bundle on my Galaxy S4, both of which are APK files I side installed and I have many apps from both installed. I don't think I'm a minority in that regard, since these are businesses. As such I have lots of apps not from the Google Play Store. My Kindle HDX doesn't even have access to Google Play, so all the apps on it are from Amazon/Humble Bundle. They're just blown up phone apps for the most part.