> Do you expect a prompt for every website you visit (Would you like to allow permission for Firefox/Chrome/whatever to view/store your password for "abcd.example.com"?)
This is pretty much exactly how macOS Safari prompts, and has for several years, at least in Touch ID scenarios. It shows a suggested username/identity with a Touch ID icon next to it, presented just like a normal autofill suggestion otherwise.
The per-site prompt and the inclusion of username/identity are really good signals, and feel like they reinforce the opposite of Windows UAC. They definitely gate access in a similarly repetitive way which encourages repetitive acceptance. But they demonstrate prior authorization that would have to be manual at least once at some point before the prompt, and you won’t be promoted the same way for sites you didn’t manually authorize first.
It’s a good enough signal that I generally use it as my first line of defense against phishing/domain spoofing. If I don’t get promoted for credentials for a service I expect to have an account with, I’m immediately suspicious. That doesn’t mean I automatically trust or distrust on that alone, but it’s a pretty decent sniff test.