What is the use of tennis strings? An obvious answer is that they are to be used in the game of tennis to give the player fun, health and satisfaction.
Only the player doesn't have to be human. Tennis strings have given my cats lots of fun, health and satisfaction. Whenever my tennis racquet has a broken string and the set of strings have to be removed, I will keep some of them, roll each piece into a sort of round shape and turn them into one of my cats' favourite toys. They will chase and 'attack' the string like mad until they accidentally thrust it under the sofa. We always find two or three pieces of tennis strings under the bed or the sofa when vacuuming the floor.
I am particularly pleased to see how the strings help sharpen the senses and boost the confidence of Piper the blind cat. After detecting the location of the string using his auditory faculty, he would hurl at it and attack it as if it was his worst enemy. The level of contentment and confidence Piper derives from the strings probably exceeds what I get from the strings in my tennis racquet.