70 Dart manual brake to power brake swap

There are no modifications needed. I ask... Why make the change? A manual brake setup works great and weighs less. It is simpler and makes engine service easier because the power booster takes up some much needed space.
I swapped a 75 Dart power booster and master cylinder into my 70.Charger in 2001. I'm now in the process of swapping in a manual brake master cylinder.