We no doubt all have different ways of working. When I am in the workshop, for instance, periodically I will clean the work area and put away tools that are surplus, etc. At the end of some work period I generally put everything away and clean up. When getting going with something I like to just start, not spend time clearing up the last mess before I can even think about what I was going to do. Perhaps my PC workflow follows that kind of mindset.
But, particularly with PCs, what happens if you get a powercut? Or the cat walks over your keyboard during the night? That's a lot of work to try and figure out if you need to save whatever changes, of if it's changes to revert.
The other reason your kind of workflow doesn't work for me is because things one often sees tend to fly under the radar after a bit. My bench has loads of half-finishes projects, some of which I forget I even started, because I put them aside to do something else, and after a bit they are just bench furniture.
On a practical level, turning the thing off saves me 250-300W. I just checked and counted 12 mains plugs (or wallwarts) which are switched with the PC, so that's a fair number of potential fire sources to not have nightmares about too