3. Air under low pressure escapes slowly in comparison to air under high pressure. This decreases the likelihood of having to fix a puncture on the road.
4. Fat tires hold a lot more air than skinny ones, so it takes longer for it to get so low that you can't ride. This decreases the likelihood of having to fix a puncture on the road.
I discovered these truths a few weeks ago. Coming home late one night, my front tire was low. It was still firm enough to ride, and I rode gently. I got home without stopping. By morning the tire was flat. I patched the tube in the convenience of my home. This was a 650x38b tire. Nice. I hope I get to keep them. They seem to be stretching and are threatening to rub against the frame which was built for narrow 700c tires.