Commuting wears you out. The energy and stress saved from not having to drive in bumper to bumper traffic or ride public transportation can add a good deal of productivity.
And I found that going for a walk or something like that to replace the commute didn't have the same effect, for a number of reasons. There was the mental hurdle of forcing myself to try taking the walk instead of going straight from A to B since I was already there. There was the fact that while I could try to flush home concerns from my mind on the walk, coming back to my home where all those home concerns are right there for me to notice when I walk through the door meant that all that mental flushing was for naught.
Now I admit that I am fortunate enough to have a commute where I'm rarely in bumper to bumper traffic, and it's less than a 30 minute drive. But at least for me, a commute is a vital part of my work routine.
I was childless and petless then though. The thought of squeezing everything in between school drop-offs, pick-ups, after-school scheduled activities, and dog walks is when things get really annoying.
Then I moved and now its a 30 min drive. Not a nice commute.
Latterly I had about a 30 minute driving commute again but I was doing so much travel that I wasn't consistently in the office that much.