The value then is entirely in believing that your guys have your back if you’re hurt, which I can imagine has a massive effect on morale. I suppose the existence of dedicated medevac also provides some constant reminder of humanity, which also has a similar effect plus the additional motivating factor of outrage when your med guys are hit.
Of course I could be entirely wrong and we could be frequently rescuing soldiers and putting them back into duty quickly. Curious to see what the numbers say.