Google lost with Epic Games, where they now need the Play Store to a third party to allow other app stores to be offered as well as not requiring users to use Google Play Billing for any payment. Recently, Microsoft also wants to take advantage of this matter.
Microsoft will sell Xbox video games through the Xbox app on Android. Not only that, each of these games can also be played directly on Android devices via Xbox Cloud Gaming. This means, PC and Xbox console games can be played through streaming services. It's a little strange why the Xbox app still doesn't sell video games while the Steam and PlayStation apps can.
Anyway, Microsoft still doesn't have any further information about this brand new Xbox application. Support for game purchases and play on Android devices will also be limited to users in the United States.