In the office I can go take a nap in my hot car. At home, it's in my bed.
Office: a walk around the office building and cars/traffic. Home: go outside and water my plants
Office: take breaks with co-workers or no-one Home: Play with my baby/spend time with my wife.
Peer pressure, external distractions from colleagues, etc. You can get a break in-office, but the distance you can get pales in comparison to working from home. It's legitimately one of the best productivity and mental health decisions I've ever made.
The ability to walk away when you aren't being productive and soft reset is one of the most valuable aspects of working from home, IMO.