I agree, but...
I am on septic (tank I should say)...
The
only reason I have a GD is to make sure whatever goes into the drain by-passing the drain basket from washing dishes (or pre-wash before the DW) is finely ground. It is a mute subject actually as if you have a DW on septic, it too will discharge food particles, how finely ground no one knows.
It is a convenience and as long as you understand the possible results, there should be no problem.
As for grease (and soap scum buildup due to hard water) a home grease trap is available but I don't want to clean it personally...
You guys that live out too far for trask pick-up. Have you thought about a trash compactor for garbage?