For several layers and long seams a walking foot has its' advantages. I don't know how the knitting foot with the moving finger on the needle clamp works. It looks like there is a bit of presser release action when the lower feed dogs are in upward motion (moving the fabric). Flimsy jersey can stretch during sewing, and I guess it lessens the problem. My trick for jersey has been to lower the presser foot tenison, no drag or anything for simple seams like joining pieces, cuffs, hems... Then I just use the basic zigzag foot, and just a stretchy stitch pattern. For the odd job and garment you don't need an overlocker, just a good basic machine. The main advantage with the overlocker is the two needle stitch patterns; they are different than the one needle patterns on the regular machine. There's of course the neat edging with the cutting knife. With a few exceptions a basic machine has less stitch width than an over locker, and less speed.