Also known as grafting bind off and long tail tubular bind off (and probably a few other names). It matches the tubular cast-on. They both make the edges of 1×1 ribbing (k1, p1) look super snappy and make the edge stretchy without flaring. It’s worth learning and worth the extra time it takes to bind off this way, as seen on the hem & sleeve cuff of my Old Town cardi. (In an unusual turn of events, I appear to actually be patting myself on the back for nice finishing work. Weird.)
Today I learned that it’s also possible to “knit” kitchener stitch; I say “knit” and not knit because you’re still pulling the working yarn all the way through the stitches, you’re just using a knitting needle instead of a darning needle to do it. It’s probably a good way to learn kitchener stitch, but I’m going to stick with the darning needle, which is really just a short skinny knitting needle with a hole in it anyway.