Less distraction? Unless you are doing cookie cutter crap, you sometimes need to be able to walk away from your workplace for an hour or two to have good ideas; frankly, I've worked with some of the best scientists on this planet and it was common to see them leave their desk for an hour and walk around the block to clear their mind once a day or so.

Moreover, I recently fell into the trap of working for an entire week nonstop to solve a really hard problem. Took a few hours off one day to clear my mind and when I came back, I had the problem solved inside of an hour. If I continued down the route I was going down before that time off I can guarantee you it would be more days wasted.