I've worked with many devs who think they can work those kind of schedules and be productive the whole time, but I've yet to work with one that actually was.
On the other hand, I've had to send people working for me home after getting pressured into having people work long hours to finish a project and having people snap or become so unproductive that it was a net drain on the team.
Mostly when people do crazy schedules and think it works they have lots of downtime they simply aren't paying attention to, e.g. drawn out morning rituals before they do any actual work; lots of breaks. And they'll simply just slow down and make more mistakes.
It looks like it "works" because people seem busy the entire time, and seem exhausted at the end of it, but being busy and feeling exhausted is not an indicator of being productive.