I wouldn't use them for hand quilting. As Crashnquilt said, they are great for burying knots when machine quilting. For some quilts, you don't want to have your starts and stops show, so you tie the bottom and top thread together, then thread in between the layers of the quilt, popping the knot into the fabric. It doesn't take very many and you will really like the spiral eye needle.
I did try the traditional self threading needed, but 1) it shredded my thread and 2) after 100 or so knots my fingers were real sore with the two little spikes on the top of the needle. The spiral eye needed threads on the side, so your fingers have a nice rounded to push instead of two little spikes.