I think the purpose of the double fold for binding is to make it wear well. If you have any old quilts, you will notice that the binding is the first thing to show wear. I would imagine a double fold done this way would have bulk in the corners but for wall hangings or things that didn't take lots of wea,r it sure would be simple to do and very easy to get the square corners. I have a Christmas project I think I'll try it on.