Somehow, I feel that some divers mock shallow dives and pool dives as "non dives". However, for a beginner, and with a good instructor, practicing buoyancy control and maintaining bouayncy, safety stop depth buoyancy, etc.. is more difficult in a pool or shallow depths than a square dive to 90 ft. Of course, you can fog up your mask to mimic poor visibility, ha, ha...
One certainly forget to do air management at these depths, but a good reason to limit beginning divers to shallow depths perhaps is to force them to develop better buoyancy skill, and one of the reasons to insist on a 15 ft safety stop is for them to understand the need for proper weighting so they can main a hover at this depth with a nearly empty tank.
An hour in the pool practicing these skills is better than 40 minute burning air at 90 ft, in my opinion. 30 minute in a pool refreshing basic scuba drills in a refresher course is better than 10 successful dives to 90 ft where you did not practice basic scuba skills.