Yes, the foot pedal and Dynamic Arranger do a similar job, but in different ways... The footpedal strictly regulates volume alone, whereas the DA works with strictly velocities. There are subtle (or not so subtle) differences between the two, especially with those mentioned vel-switched sounds.

Drums particularly benefit from small amounts of it, as often it's not enough to make a gross change in the volume, but usually just a few ticks is enough to push kick and snare into harder hit velocities. More of a timbral change than a volume one. VERY drummer like (who can rimshot quite quietly, when they WANT to! )...