I've heard that it's supposed to give you a crisper edge when applying your binding, but I've only done a little bit of serging and I'm not confidant of my serging abilities that I could feed the quilt through accurately - I'm worried I'd slice off too much of the edge.
I do sometimes use my machine and my overcast stitch if the border had a lot of seams along the outside edge. I also find that using my iron when I bind works great. After stitching on the binding, I press the binding out (so you're getting a good fold at the seam line). Then I fold the binding over to the back (or front, if doing my faux piped binding technique) and press so that the edge gets a good fold. I find doing this helps me better sew the binding down, whether doing so by hand or machine.