You still need to do your full commute every day, twice a day. So you don't get the full range of personal time available by reducing your hours. You also lose

You still need to do your full commute every day, twice a day. So you don't get the full range of personal time available by reducing your hours. You also lose the advantage of having a free day during office hours for personal appointments. I would also argue that (for me at least), a 6 hours day will be just as stressful as a 7 hour day.