I think Sign in with Apple is a step in the wrong direction. While I consider Apple to be a good company I don't:
1. want any company to know what services I am using
2. want to place my login credentials in an internet service
3. make a single point (this Apple service) a so prominent target to be attacked
Since there are already (better) alternatives like FIDO2 (see Heise Security) that replace passwords with a pair of public/private encryption keys - even with the possibility to store the private key in a password manager app, I don't like this service at all.
Maybe it was driven by the intend to bind customers to the platform, what is understandable but not so good in the end.
Well... you have to meet one basic requirement, and that is the solution must be realistically accessible to the general public. Not only does that mean it must be technically discernible, whatever company/organization offers the solution must also be ubiquitous enough that the service is adopted and trusted. I'd add that the offering entity ought to be one which will stick around, as credentials will be tied to the service being offered, and one not likely to be acquired later by an entity dedicated to data collection and resale/advertising.
Authenticating through individual services directly is certainly the old-fashioned solution which doesn't tie credentials in any capacity to a ubiquitous company, but it is far, far less secure in terms of security (the breach example you gave) than authenticating through any of these services.
I disagree on the fundamental point and am quite glad that Apple is hopping into this game. My reason is that the other companies offering this service are also companies which are interested in data collection and advertising. They are not interested in our privacy. Apple, however, will genuinely endeavor to secure and privatize this connection not just relative to these other entities, but compared to authentication with an individual entity through the traditional means, and that's what I'm looking for. Any of these services are also far, far less likely to be meaningfully breached than accounts with individual entities.
Another benefit to these services is there are fewer credentials out in the wild to manage. For someone who is technically competent a password-managing services like 1Password is adequate, but "Sign in With Apple" (and "Sign in with Google" or "Sign in With Facebook" is much more convenient and easier to remember.
There's not much of an upside for entities which are invested in customer data collection to use "Sign in With Apple" for these privacy-related reasons, which is where the condition of inclusion (restrictions noted) for release into the App Store is going to come into play.
Knowing you're an apple user is another data point to build a unique profile to track you.
This is wildly nonsensical. It sounds more as though you're trying to disparage this service rather than subject it to any degree of critical thought.
Any of the other data collection services can trivially identify if someone is accessing their service on an Apple device. This data is exposed simply by interacting with an app or website. Whereas obfuscating a wide array of far less trivially obtained data points is a solid benefit to considering "Sign in With Apple" over other "Sign in" options from companies interested in data collection, as well as providing the information which would be obfuscated with "Sign in With Apple" directly to a company.