Because Skype allows you to use the digital content that you buy outside of the Android app. (Desktop, Web and so on) Apple has a similar rule. (We have an iOS

Because Skype allows you to use the digital content that you buy outside of the Android app. (Desktop, Web and so on) Apple has a similar rule. (We have an iOS App in the App Store that uses Paypal) Edit: Here's the relevant part from the TOS: Developers ... must use Google Play's in-app billing service as the method of payment, except: ... ... where payment is for digital content or goods that may be consumed outside of the app itself (e.g., buying songs that can be played on other music players).