Yes, but side-loading, either directly or through third-party stores, prompts the user with dire warnings, making it almost impossible for developers to realist

Yes, but side-loading, either directly or through third-party stores, prompts the user with dire warnings, making it almost impossible for developers to realistically use that method. The exceptions are hardware manufacturers that ship custom versions of Android that have their own stores. If it weren't for that detail, or that Google warned all installs about the same thing (even from their own store), I wouldn't have a problem with it.