A lot depends on how you use filter socks. If you are the type that just lets them overflow and don't clean them until absolutely necessary, then you are just using them as detritus traps and lessening sump accumulation, basic mechanical filtration, which is fine. In this case I don't know if it really matters if you use them or not. Not using them just means you will clean your sump more often.
But if you rinse them every couple days then you are also performing another function by removing waste before it degrades into nitrate, probably mostly uneaten food, I would guess, maybe some other stuff coming off the corals.
I use them both ways. In my mixed LPS/Softy tank I wait until the socks start to fill up with water before rinsing them because I am not looking for ultra clean water in that system, but in my SPS tank I remove/rinse every couple days because in that system I am looking for ultra clean water.