The engineering that went into creating this foot's design is astounding. The back of the needle slot in the foot is contoured to help deflect your needle if it flexes and therefore minimize the chance of you breaking your needle. It is intended to be used with Jean needles that have a sharp tip which can be damaged more easily than regular needles. They are made particularly robust to penetrate denim and other sturdy fabrics. If the needle bends backward, the jeans foot "catches" the end which helps to prevent it from breaking. That's why it's perfect for sewing or mending canvas, denim, upholstery, pillows, seat cushions, slipcovers, and other durable fabric projects.
It is the best foot for most projects as it feeds the layers of fabric together with very little slipping or shifting. This foot can also be used with any type of fabric if you are just doing a straight stitch for the best-looking stitch.
For the best results, I recommend that you use it with a straight stitch plate to get the best stitch precision.