Conceptual art is the first step in the mural process. It allows for us to show the client an actual version of what can be expected from their mural, and it allows us to trouble shoot the design before we go large scale with it. The revisions can be made before the paint cans are even opened, which saves everyone some time.
Some of the murals turned out to look exactly like the sketches, but in most cases the painted versions look much nicer than the concept art. (Go see the Mural gallery to find a few of these in painted form.)