I should have prefaced that by "Conditional on high IQ".
If your IQ is 80, that's a really useful habit. If your IQ is 140, not that much.
Note that being able to focus and apply yourself is a highly useful skill for everyone, but that's not quite what we are talking about here.
Confirmed that application and focus is a somewhat different thing (though related, in my case at least), and we're talking more about conformance to imposed schedules and external expectations of monitorable behavior.
Disagree that it's not useful at IQ 140. It's a lower proportion of success than for someone closer to the mean, but still a nice still to have and removes some barriers to establishing one's talents.
Also, I'm comfortable with not having significant accommodation for distant outliers. Actually, for such people, the habits and skills of not getting killed by one's "peers' is pretty important. High school sucks for those it's not evolved/equilibriated for, but it's temporary.