When you start dumping a full bucket, you have a lot of weight with a big mechanical advantage pulling on your cylinders. As seals wear, if hydraulics can't keep up it sucks in air & causes floppy bucket problems. And nobody respects a floppy bucket.
The solution is regen or fast dump. It puts fill hydraulic pressure to both ends of the cylinder. As the but end has more surface area than the rod end (there is a rod taking up a lot of space) it overpowers things to still extend. The extra fluid from the rod end can now go in to the but end of the cylinder filling it faster & preventing it from sucking in air.
Most machines these days use regen as the primary or only dump function because of this.