Pulse Spins Shortening Life
Only reason I can come up with is the extra load on the motor's windings from drawing extra current to do that. Like highway driving vs. stop/go driving in a car. The latter uses more fuel and *can* wear out cars faster.
Given the machines were designed for intense laundromat use, I doubt this was a concern. Plenty of them truck on each and every day.
Its probably more of a means of allowing the pump to keep up in an over-suds situation, or to ensure out of balance loads are given a chance to resettle, given a lack of balancing/over-suds logic on the older models.