I probably wouldn't call it "basting strips" ...
... but the way your instructions read, you are creating a "flange" at the outside edge, next to the binding.
You are "basting" them to hold them in place, temporarily,
then they are properly sewn in place with the machine stitching of the binding.
Re EasyPeezy's link ... the flange and binding are one piece together, attached to the back of the quilt, then folded to the front, and machine stitched to finish.
Whereas your instructions ... the flange is created by the basting strips, and the binding is machine stitched to the front, folded to the back, and then, you hand stitch it on the back of the quilt.