This will enable phishing campaigns on an unprecedented scale.
Many people will lose their funds because they do not know where to download wallet APKs and verify PGP signatures.
People get tricked into downloading and entering their seeds in fake phishing wallets they see on services like the Play Store or the App Store all the time. It helps only to some degree. If they want to be in bitcoin and crypto, they will have to learn how to protect themselves or face the consequences of their actions.
While removing these from their stores might look like a big problem which I don't see as one because all those are centralized platforms and that's the reason they are feeling too powerful and we can still download from official websites, there is a bigger problem.
That depends. If you are using Android, you will most likely have alternatives to get the apps you need. But if you have an iPhone, you pretty much stuck with the App Store. YOu can always jailbreak your iPhone, though.