So I suspect they have experience that calls for this additional alt?

I haven't a clue on the power requirements of the push button sail handling equipment, but thinking of how much you can grind sheet winches, mainsheet, furling sails a few times, in daysailing or sailing for fun in and out of harbors, you could burn some amp hours. Occasionally, I sail that way and the winches make a lot of noise.

This also had me thinking, in much of my typical sailing, I do very little "work" handling sheets. So I guess the actual power needed for this stuff is completely individual to each sailor. Plus, if you're going to invest this much in the equipment, it makes sense to have the energy aboard to run it.