[derefr]

I would assume that it means that if you're publishing an app on both the Play Store and alternative stores, and your alternative-store versions of the app offer alternative payment methods, then Google will shut down Play Store distribution of your app as punishment for that.

Apple (briefly) tried to do something like this previously, where they tried to force apps that offered no free-to-paid conversion through the mobile app, only through the web, to pay the "Apple tax" on the subscriptions made through the web, because they were for a backing service that had value for customers almost exclusively due to its use through the mobile app. Nobody was willing to put up with this, though, and they quickly walked it back.