Spinning also produces less fatigue.

Consider kicking off a 418 mile supported tour with a 6000' climb including a 20 mile, 4700' stretch averaging 4.5% and reaching 6%.

Ending the day with extra Cliff bars isn't going to win you anything, but having the legs left to finish the day quickly will get you a prime camping spot with no line for a hot shower and still feeling good tomorrow will make the following 330 miles and 24,000 feet much more pleasant.