I'm a big believer in this workflow and generally agree with all the guidelines about when to do and not do this.

Code review has value, but I don't think we are always honest about the costs. At most places I've worked, there has been an informal understanding that code should be reviewed within 24 hours or so, but there is a world of difference between getting a review within 2 hours and 23 hours.

If you have to go back and forth a second time, it's so much more likely that the approval comes much later due to straddling end-of-day in someone's timezone.

Tangentially, if you are designing policies for code review at your org, try to think both about minimum requirements (e.g. PRs should get a first look within 24 hours) and typical requirements (e.g. most PRs should get reviewed within 2-3 hours). What typically happens is what determines overall velocity for your org, so it's much more important than whatever strict SLA policy you have. These are also fixable problems if you have targeted conversations with people. E.g. "I noticed X, Y, Z times, you had unreviewed PRs at the end of the day. Can you set aside some time to review code before EOD? Or try installing PR reminder?"