Brilliant idea!
I've been working on a cross stitch project on dark-colored Aida, and it was driving me crazy! So hard to see the holes on dark fabric, and I kept missing them and splitting threads. I saw these in the catalog and thought they might help. (Are they new? I had never heard of them before.) And oh yes, they do help a lot, and my stitching is going much faster now. Highly recommended if you have problems like this. Well worth the extra cost.