Why are the 11.75 Brake Better?

The Dr. Diff kit comes with slider-type calipers, that's also the type on my car currently. It's weird Hawk sells the pin-type ones it since it seems that type is less common on the popular A/B/E-body Mopar muscle cars.
Actually the E-bodies were pin type, certainly most of them anyway. Lot of the B-bodies as well. My ‘72 Challenger and my ‘71 Satellite were both pin type calipers. And later it was either the M’s or the R’s too, I know I pulled pin type calipers off a couple of the later cars in the wrecking yards.