Expertise and practice makes some of those things automatic, but not enough to reduce it all below 5-7. Further, in any surgery there will be other things going on that require cognitive attention, decreasing capacity for other things.
Everything you can do to reduce cognitive overhead makes a process smoother.
I teach the LSAT. One section logic games (officially, analytical reasoning) tests precisely this cognitive load. Students must work with 4-6 rules + what the situation calls for on question.
The rules are impossibly simple. But, in the heat of things, students just aren't capable of working with that many items unless they create a structure using diagrams. And even seemingly tiny efficiencies have an outside effect on speed and correctness.
Don't forget that these surgeons are often tired busy and stressed, three factors that worsen performance. Having a clear list that says "do this now dummy!" massively helps keep you on track even when you're a wreck.