Everyone was telling me the wall is great practice. I found it not good, there was no sense of depth or touch
My usual courts were being resurfaced so I used the wall for a few weeks. Trying new techniques on my forehand hitting drives right above the line and trying new drop techniques.
The hard drives that were just above the wall line, in the game were mostly going long, the drops I thought were neutral were traveling too far past the kitchen (to hit kitchen dinks against the wall you have to give it some speed to rebound back to you) .
The drips didn't have the right clearance/touch/distance. If you're a starting out and need coordination it's worth it but there's a lot of nuances that the wall doesn't replicate well.
I think it depends on the wall rebound too, mine are wood (not concrete) so a tennis ball rebounds ok but pickleballs need to be hit with decent force if you hit soft it takes 2 bounces to get to you and by then it's an inch off the ground but cement walls were not that much better. Possible need a different ball might help things.