The only really practical use that I have found came from my wife. She was always misplacing her measuring cup in the kitchen. So I fastened one end of a cord to the cup; and the other end to a towel rack... Now she never looses the cup and the cup is usuable anywhere on the counter...
This same idea can be used anywhere in the house with other "often misplaced items".

The intended use for these CurlyCords is to hold slot cards, but they don't even do that well. Most cards are pulled out of the slot by the tension of the cord, or the weight of the cord.
I try to use the longest cord I have, or fasten two cords ene-to-end to lessen the tension, but that increases the weight... The weight problem can be over come by wrapping part of the cord around the slot handle...