A darning foot on a regular sewing machine is not the same as a hopping foot.
On your domestic sewing machine, the darning foot just holds the fabric down with less pressure so you can 'freely' move the fabric while sewing.
A hopping foot is more common on the larger long arm machines. It actually goes up and down, or 'hops' as you sew. Another poster explained how it holds the fabric just long enough for the needle to go in and out of the fabric but then goes up so the fabric can be moved around.
By holding the fabric more firmly, it gives a more consistent stitch, with less skipped stitches and breakage.
Hope that helps.