a) They're unaware of it,
b) They don't want to do it while recording videos because, I dunno, it's a sign a weakness or "uncool" or something, or
c) They're averse to using it.
I can understand a (if you're in this group, you can at any time press f6 to save and f9 to load), but I can't understand b or c. I've seen, time and time again, somebody have to restart a level or a major section of a puzzle because they screwed something up. From my perspective, you're just wasting your own time. Sure, there's always going to be times when you accidentally jump into deadly water or screw up an easy portal shot, but if you have plenty of time and you know an upcoming move is going to be risky and cost you minutes of your time if you fail, why not quick save? I can't imagine you're having a ton of fun redoing a bunch of steps you've already done.
