I have wondered who dreamed this one up? But I believe they are code. Vents in crawl space walls? Are you kidding me? You mean they want hot humid air inside the crawl space in the summer, and ice cold air in there in the winter? Then insulate the entire floor to separate it from the hot humid or ice cold air. Hmmm, seems kind of backwards to me.
A better idea is to put poly down or a slab on the floor and insulate the walls, not the floor. This keeps ground moisture out and keeps everything in the crawl space from being exposed to outside air.