I'm completely happy hauling around a full size spare for a once in a decade blowout. Having that could easily save me 8 hours of frustration. Possibly more depending on where I am and what time it is.

I'm not carrying it for if I get a slow leak on my work commute, I'm carrying it for when I'm taking forest roads in durango, or driving across nebraska at 2am. I carry a blanket and chains in winter for the same reasons.