From a user's perspective, I tried "Sign in with Apple" for the first time the other day on Dom Hoffman's new app Byte, and I'm really happy with it. Some benefits:

1. I don't need to remember a password to sign in

2. My real email is never shared with the service I'm signing up for

3. I had a new account in like 3 seconds without providing any personal information

If any Apple employees are reading this, you guys did a great job!