If you ride on really bumpy roads, there is a very real difference in comfort between 1.75", 45psi tires and 1.25", 90psi tires.

My wrists used to kind of hurt from the hard tires hitting bumps and I would have to slow down or steer this way and that, more than I would like to in order to avoid causing myself pain by hitting bumps.

Then I started using fat tires, and life was much better