Filleting does leave behind meat. It is really noticeable on big fish. Many times when I am cleaning cobia, sharks, or snapper, people will come up and ask if they can have my carcasses. They then move to another station and start pulling out cheek and head muscles, the throat, meat along the backbone, between the ribs, and by the tail. In the end, they have a couple of pounds of free fish. Or several pounds of fish from a 200 pound shark.

Bream were and are still scaled and gutted with the head cut off. We fry them whole and pick off every piece of meat. We have always skinned then gutted catfish and headed them to be fried whole unless they are larger ones. Crappie were always filleted and still are, unless they are really short which sometimes happen in the winter on LOP. Anything under 10" gets scaled, gutted, headed and fried whole.

A true fish eater will have a nice pile of clean white bones when he gets done eating.
It's almost a lost art, and disgarding the carcass with the bones is a by-product of our microwave society!
That said, I'm also into filleting my fish as well.