I imagine they use this as a way of removing an app from a country that forbids it. But also, I think you, as a dev, pay more if you want your app in all AppStores. As other said, transport app, food delivery and other services are a pain to have if they’re not available in your country’s AppStore.

I don’t really want side loading, I just want, as a foreign that frequently goes to Brazil, to be able to install apps from the Brazilian AppStore. I can’t use many apps because they’re not in my AppStore. It seems side loading is a possibility.