The ridge keeps the mulch from slilding out in the the yard and holds it in place better to where it will last longer and not slope off in to the grass and yes it dose look better to ,, simply dig a small ditch around the area you are going to mulch and pull the dirt to the out side of the ditch
or you could buy some dirt and build a ridge around the mulch , buying the dirt would of coarse be the easiest of the two options


