Nice to see different ways to do bindings. I think the true knife edge is turned in on front and back and blind stitched at the edge. The other knife edge shown was with binding sewn on the front and turned back so it doesn't show on the front. Then sewn on the back.
One more way to make a quilt reversible is to make your binding of two fabrics. Half matches the front and the other half matches the back. I think Betty Cotton shows how to do this. That way one color shows only on the front and the other color only on the back. This is tricky to get perfect, but I've seen it done perfectly.
One other thing: when we talk about glue, I think we should always use the words "school glue" You never know when someone will see a comment about glue who has never heard about it before, and thinks all glue is the same. Just don't want someone to get the wrong idea and mess up a project.