It does seem dumb. McShay mentioned that the most impressive workout he ever saw was JaMarcus Russell. (sorry) Specifically to QBs, when you don't have to make reads and decisions, and you're just throwing a football in a t-shirt and shorts, it's not difficult to look good. I'm pretty accurate throwing a football. But I don't know how I'd do at 5'9" looking over a line, deciphering what the defense is doing, recognizing pressure, etc.