I generally do not buy coordinating fabrics. Not the matchy type, I guess. If I get in a pickle then DH helps me find the right fabric to go together.
As for the match system: As long as they offer a reasonable selection of fabrics that go together (color/scale/value/pattern/texture) there should still be the individual option to pick and chose what works for you. It's no different than going to the fabric store and starting with one fabric that you want to add to.