Gas anesthetics are part of an expensive racket. My clinic has the latest gas machines and technology and I use all the gasses as well as having utilized nitrous oxide when I performed more orthopedic work. You may be all defensive of gas now. I see newly-minted vets coming under my tutelage frequently and from them you would never guess that they are supposed to be moving rapidly. The steady blanket of gas anesthesia helps create a relaxed, careless mind that easily loses the focus and dawdles.
Clipping takes forever, prep forever, pack opening and scrubbing forever and so on.
With injectable anesthetics, you are sweating all the time that the animal will wake up. I think the good surgeon should be hyper-aware, nervous and sweating at almost all times. This keeps you awake. When people think they have all day I see them fussing ridiculously over tiny bleeders, nurturing the terrible habit of tossing suture packs, used bloody gauze pads, and other tissue trash right into their cluttered pile of instruments. Incidentally, it is just as bad to be overly anal about the lay-out of the instruments at the cost of overall time under anesthetic.