Whatever stitch you are using on knit fabrics, somehow I find that it seems to sink into the fabric more, seems more deeply knitted into the fabric. I suppose a knit or stretch fabric might have more loft to it than a quilting cotton for a start so the stitches don’t sit on top of the fabric in the same way.
For me, it always seems if I make a slip with my seam ripper in a woven, I might poke a hole that I can simply scratch away with my fingernail and move the fibers back into position and you don’t even notice it. Poke a knit fabric with the seam ripper and then I make a hole that won’t go away, the fibers are damaged or cut and can even ladder. Disaster.
Read more about it here.