If, like me, you have pressure-sensitive shoulders, load lifters are absolutely essential to take the weight off the tops of your shoulders. Properly posititioned, they do transfer additional weight to the hip belt. Whether this is necessary for you depends on your personal body configuration.

Go try on a bunch of different packs--with weight--to find out what load lifters do, if anything, for you.
May your trails be crooked, winding, lonesome, dangerous, leading to the most amazing view--E. Abbey