Presumably such services won't implement Sign In With Apple in the first place. People will accept it because they want the sheer quantity of users Apple provides.
The useful thing about Apple is that they can force people to do things they don't particularly want to do, like accept anonymous e-mail addresses or stop using Flash. (unfortunately this is also the bad thing about Apple)
The useful thing about Apple is that they can force people to do things they don't particularly want to do, like accept anonymous e-mail addresses or stop using Flash. (unfortunately this is also the bad thing about Apple)