Chainstay protectors can protect the paint if you ride on rough roads, which is why they are more common on MTBs. I've had road bike that came with them and others that didn't so they are not universal. If you want to replace yours, Lizard Skin ans Bontrager (Trek) offer them as aftermarket items or you can make your own with Gorilla Tape or similar thick plastic adhesive film. Be sure to clean off any residual adhesive and any oil or dirt from the chainstay before applying the new protector or it will come off just as soon.