I don't know, think of it as the reverse of FastPass. There are days it takes the better part of an hour to get to MK. That's time that probably cuts into shopping and store browsing more than riding. More efficient monorails with higher capacity means happier guests with an extra 15 minutes in their day.
(At the very least, I'm assuming these monorails won't (1) break down several times a day, and (2) be flush with the station to eliminate the need for wheelchair ramps. Both are time-savers. Any addition in capacity or speed would be a cherry on top.)