ALL decorating books say that to display a collection one needs three of the item. So you did perfectly and I would leave them as they are and display them as decorations.
Awesome find!
You could use them to wrap your quilt binding around to keep it from twisting. Same for jelly roll strips that have been sewn together (if the spools are wide enough).
I've bought some of these large thread spools at a flea market. I use them to decorate around my house. I place sitters and what not's on them. I love them.