If you have identified your inefficiency, have chosen some sort of mobility routine that will help address it, and accomplish the increase of body temperature and synovial fluid, then I would go as far as saying the warmup is sufficient. If you don't have a mobility routine and accomplish those other two tasks in another format (walk/jog/dynamic stretching/whatever), I would say you are right, you may just be prepping your inefficiency. What constitutes a sound warmup is a tangent we could take up another 4 pages on.
As for doing it daily...we all have things we do daily from read the paper, drink our coffee (I've started grinding my own beans... seriously if anyone hasn't done this, buy a grinder and french press. Smell, taste, experience is that much better, plus there are so many bean varieties to try and the coffee just tastes so rich) to mentally and physically prepare us for our day. For some, this includes OS. Is there potential for a placebo effect? Absolutely, just like anything. It could accomplish absolutely nothing for somebody yet they feel better. Personally, since I started I see benefit in mental state when I do it upon waking, and am seeing benefit in my strength journey so I will continue to practice it.
I have very much enjoyed this discussion (no sarcasm), but I don't want to turn this into a back and forth argument on the benefit. Works for some, doesn't work for others, many viewpoints have been expressed.