I like this feature. I spent many, many months playing a very careful game to earn my HAU's and if they die, either I revive them or lose them forever. On the rare occasions when I accidentally failed to revive one I certainly didn't mind paying the same 45 diamonds to have Support do it for me, but it was slower for me, and an extra ticket for them. This feature is welcome.
But what happens when the hospital fills up? Will Support still be willing/able to do revive my HAU for me, as they have before? Or will I have to spend diamonds to free up space by reviving unwanted rogues? And what happens if I'm (oddly) willing to do that, but don't notice that the hospital is full, and then lose a unit that I would want to revive?
I suggest a small tweak to this feature: free up hospital beds by allowing any chosen unit to be either revived, or deleted permanently. Maybe as well as the heal button, add another to delete the selected unit permanently (and a pop-up warning this action cannot be undone).