I'm a film editor. None of that stuff is stuff I care about, tbh.

Straw continuity? I think if the viewer is watching the straws there's something more seriously wrong with the film.

Clock continuity would only really be an issue if the plot centred on time (24, for example, or a bomb that's scheduled to go off at a certain point or whatever). Otherwise why is the audience bored enough to be looking at that?

I even liked the eyeline being low, although it massively changed the performance (made him seem like he was shirking the issue, which I quite enjoyed).

There are serious errors that occur without a script supervisor, however, that this video doesn't mention. A character running on in the wide shot and walking on in all the others, for example, means that you can't use the wide and thus have problems establishing place etc. Or a character who is really angry in all the shots taken in the morning and then super chill in the rest of the coverage which was taken after lunch (or even a day/week/month/year after) means you can effectively only use half the shots.

I agree that script supervisors are vital to the success of a film. But flagging up the placement of objects is the least of what they do.