That way they will not rub and wear holes in the tube. A paper clip works as a perfect replacement. Tie wraps are used to hold broken pieces in place long enough to finish the ride. Tape has many uses. Holds broken pieces in place long enough to finish the ride.
Some riders wrap some duct tape on the seat post or elsewhere on the frame.
Rubber bands are for the same reason. The piece of skinwall from an old tire is used to make a temporary patch for a cut in the tire. Not unusual to find the tube bulging out of a cut in the sidewall. Put the patch inside the tire and put a few pieces of tape on it to hold it long enough to get some air into the tire. When some spokes break, sometimes you can tighten a few of the other spokes enough so the brakes don't rub.