Google Play Store has more than 3,000,000 apps to meet nearly all kinds of needs. But there are 11 reasons that you might have to download apks outsdie of Google Play Store.
1. You can't access Google serives because Google is blocked in your country.
2. Your tablet or smartphone doesn't have Google Play service installed.
3. App restricted by location. There are always some new games running test in some countries. Your country are not that lucky. Believe or not, Pokemon Go is not available in China.
4. App is not free. But you want a deep look before purchase. As we all know, there are lots of scam apps with a deceptive title but do nothing helpful.
5. Your device will run the app, but Google Play says no. Its compatibility test sometimes sucks.
6. You want a backup of the app, but Google Play doesn't provide the apk.
7. You don't like the new version of some app and want to recover the previous version. But Google Play provide the latest version only.
8. You wanna some apps to save videos from YouTube.com. These apps can't be found in Google Play.
9. You wanna some apps to download mp3 or movies. These apps always get banned by Google Play due to copyright complaints.
10. Many developers choose to publish test versions of the apps in forums or social medias. These apps can't be found in Google Play Store.
11. You like some apps and they works very well. But they have been removed from Google Play Store because the developer account was banned by Google. You can't get them from Google Play Store any longer.
There have been quite a few articles related this topic on steemit:
How to install APK from outside of Google Play Store and get back the missing half fun Top Practical Apps Banned On Google Play Store How to download region-locked apps from Google Play