That matters only if you pay someone else for machine time. If you own a decent 3D printer, you just leave it on and occasionally fix whatever issue is messing up the ongoing print.

Except that requires you to babysit the printer. There isn't a "good" way of monitoring longer prints. Either you spend time just sitting next to the printer constantly, or you walk away and pray it works.

True, but that reduces the problem to "not possible for everyone". If you work remotely, and have a printer next to your computer, it's entirely doable. My coworker set up his printer at his parents' house, and built a system for remote control & monitoring, including a camera pointed at the print bed. He does remote prints this way.

once the first layer is done clean, you can leave (and most people who have long running prints have video cameras watching). I do overnights all the time and rarely have problems other than running out of filament