I have been doing landscape management part time for 7 years and I can tell you unless the ground is level or on a perfectly even slope that steel junk will come up out of the ground and look terrible. Some people like to leave it exposed a bit and then it's a pain cause you have to trim around it when mowing the grass otherwise you destroy it with the mower or leave tall grass. Grass will also grow up into and through that stone and rock layer, and you will have to pull or spray it. I have an Echo bed shaper that cuts an amazing natural edge. My customers love it.