It just makes it easier to use - meaning less glue code. Making CoreData Swift + SwiftUI native approach. Where currently you'd have to make a Core Data class wrapped by a @Observable Class.
Most definitely
Then there probably won't be a difference in performance
There certainly could be. SwiftData @Models aren't subclasses of NSManagedObject, and don't have to use the Objective-C runtime for dispatch, or the KVC-style property accessors that Core Data uses.
The fact that it is built atop Core Data's persistent stores, cloud sync, etc. doesn't mean that it's a fascade in front of the Objective-C APIs.