What we get out of it (relative to the movements we perform against the wall): dynamic stabilization of glenohumeral joint and shoulder girdle, arms, and abdominal musculature in general, along with posterior musculature (erectors, glutes, hamstrings) along with improved general work capacity.
The reactive/elastic nature of the exercise ensures additional benefits to speed-power athletes; even though the physiological nature is extensive.
Research dynamic stabilization as well as perturbation training and it will become more clear to you.
I highly recommend this type of exercise regardless if the objective is high sports performance or the personal training of pedestrians. The actual ‘feel’ of these types of med ball wall rebounds is really nice. Similar to tempo in that it’s challenging in the moment yet very fast to recover from with the additional novel result/sensation of blood flow through all of the active musculature throughout the upper body.
Low cost: high benefit is always a winner for me.
Video probably won’t happen as typing is about the extent of my motivation right now.