I mostly use my serger in garment construction, and hems. It's good to finish seams on denim shirts and fabrics that ravel. I've also used it to stich around edges of fabric before prewashing to prevent raveling.
I did use it to serge silk squares together to make a quilt for my mom. It sure made sewing the silk much easier. If I have old towels that are raggedy, I cut them up and serge around them. Makes good rags, washcloths, and dish towels.