In the US nuclear navy, the power plants have to be manned 24 hours a day both operating and shutdown. Ships in maintenance periods also generally go through a phase where ship personnel have to support maintenance work around the clock. Additionally, some parts of the training pipeline are run 24 hours a day.

I say all that to say that while I am not a subject matter expert, I have a significantly above average amount of experience working various types of rotating shift work as well as duty rotations (a duty rotation is working 24 hours every 2, 3, 4, or 5 days depending on available manpower. Yes, you read that right - for a month, I was at work 28 to 32 out of every 48 hours).

Forget 4 8 hour days, I would work 4 10 hour days right now in a heartbeat with no discussion or regrets.

1) it is invaluable to have a normal working day where you can do tasks - change your oil, get your haircut, go grocery shopping without a crowd, see a matinee, the list is endless.

2) the scope of weekend trip you can plan across 3 days instead of two is exponentially higher. So much room for activities.

3) time after the working day just isn't that useful. Drive home, eat dinner, now it's 630/7pm. Waste a couple hours, go to sleep. After a 10hour day, the time after work is precious and useful to relax, but then you get a whole other day off.

It surely isn't for everyone, but it surely is for a lot of people. The thing that blows my mind is no one is even willing to try.