> What % of Android users actually want this? Do they know or care?

Bold of you assuming they're doing for users. It's fear-mongering at its finest - using the threat of security to install more control that has little to no protection against the said threats.

Now you might say it's going to raise the bar for the scammers, but nobody is going to be spending time on writing scam or malware for a few bucks. When the reward is high, they can just pay out already verified developers to distribute their builds under their accounts, or just find a workaround (fake ids?) which could be still way cheaper than the potential revenue potential of a successful attack. It's just an inconvenience that didn't existed before.

This is just a policy directly targeting the legit developers distributing apps to work around some of the platform's limitations (ie. uncrappifying youtube). They were previously free to share the workarounds they've developed for themselves since it was just as easy as sharing your APK. Now with added threat of losing your developer account and probably being perma-banned from google, those devs are less likely to continue distributing their workarounds.