Oh, Marg.
I was using this to plan out a free motion design. So my goal is to stitch the free motion designs onto the fabric without marking for the most part. I know, it sounds scary, but with practice, I'm getting better.
So you are right, this is more of a "what design to use" planning tool.
I have difficulty marking designs on quilts. Do you? So my solution is not to mark, but just do the stitching free-hand.
I'm getting better with every piece I do. I've only done small pieces so far.