There are still over 200 updates shared between iOS 13 and iPadOS 13.
It’s not exactly like iOS 13 got 3 or 4 updates. iOS 13 and iPadOS 13 share over 200 new features.
I’ll admit that the keynote didn’t explain the shared updates, though. For instance, external drive support and the additional editing gestures were explained on iPadOS without really explaining that they were also available on iOS.