Satisfaction and economy are two reasons that come to my mind to justify why I tried and make toys for my Dafne, the English Bulldog. Dogs love ropes (shoe laces as well) and although several toys that you can buy, ready-made, already resemble or incorporate a cord in the design, a real cord gives you the chance of designing the shape you wish and save some money.
You need the cable ties to limit the fraying that your cute pet will cause to the cord ends. As with all pet toys, you should check that there are no bits about to become loose that your ferocious little beast might swallow. You need the cable ties also to shape the cord the way you want.
You may wish to select a different diameter for your cord, to suit the teeth of your little beast.