I'm confused about "Chunky Binding" Is Chunky just 1/2 inch exposed vs. 1/4 for normal binding?

No, it is not.
Sorry, I didn't explain it very well but the video link in post 10 describes it at 6 min 20 sec mark.
A chunky binding in this case is using the width of binding that would normally cover a 1/4 inch batting/quilt sandwich but instead of leaving 1/4 inch of batting/quilting sandwich exposed after stitching the binding to one side you leave 1/2 inch batting exposed.
So you are squishing double the width of batting in a binding that would usually fit only 1/4 inch of batting.