I use a serger to overcast the raw edges of fabric before I wash it.
Occasionally I will use the serger to overcast the edges of a quilted top before I put the binding on.
If I have a pieced border on a top, I will stay stitch that about 1/8 inch from the edge to keep the pieces from pulling apart before layering it with the batting and backing.
If I have quilted pieces for something like a bag, I will serge the edges to get a nice finish.