All 4 cards mean something in your PLO starting hand and little differences can change your hand quite a bit. Take these examples for instance:
-KhQh6s5s and KhQs6h5s
-AJT6ss and AJT7ss
In the first example you have the same KQ65ds on the surface, but if you look closer you can see the 2nd combo is actually quite a bit stronger having two larger suits instead of just one like in combo #1. In the second example you clearly can see that combo #2 of course should be stronger due to the 7 instead of the 6, but it is actually a pretty big deal that the 7 is connected to not only the ten, but also the jack now as well.
Pay attention to how large you suits are when double suited and how connected your 4 cards really all are. They can make big differences in your game!