With Essentials, individually selected designs can have a basting stitch added automatically. This is useful when you want to add a layer of stabilizer or some other material before the sewing of a design.
But with Enthusiast, a basting stitch can be added to the hoop, which allows for a layer of topping stabilizer to be basted in place before any designs are sewn. A typical use of this is to add a layer of water-soluble topping to a towel, which will prevent the terry cloth loops from coming up through the embroidery. It can be hard to hoop a towel, and the topping stabilizer will want to slide around before the stitching happens, so basting it first can make the process easier.
The basting stitches are added to the start of the design or file, and are added as a separate color; naturally you can use any color you want to sew the baste.