On raw performance might, the M4 really does live up to Apple’s promises, should deliver. Single core is up about 20% compared to all M3 chips and more than 40% compared to M2. The generational computational leap from the previous M2 iPad Pro is at least a 42% jump on single-core and multi-core.
It’s the same reason Macs don’t have touchscreens. If they can both do the same tasks, why would you buy both? And LOTS of people buy both.