porkbao Play Services has less privileged access to the system than it does on typical Android, so it's not really fair to say it's the same as typical Android once you add Google services.
Also, the point of GOS isn't simply to avoid Google. It's also got a bunch of security and privacy features that are missing in standard Android. AFAIK, it's a perfectly reasonable use case to say "I want all the Google services, but I want the added security and privacy features of GOS."
Or, you could say, "I'm going to avoid anything Google."
Or you could do something in between. No matter what use case, though, you'll typically have the option of improved security and privacy, compared to standard Android.