These are one of my most-used items! I use them not only for sewing bindings, bags etc, but also checking the 'fit' of binding on my quilts so there no joins at corners.
I also use them for clipping fabrics groups together for class and sorting appliqué shapes. Every time I lend some at class, the borrowers says she's going to buy some!
Just recently I used them to keep all the squares for my twister separate - as I cut them for sewing and again after I'd used the ruler to cut out. Much better than pins - no marks and no blood, lol.