other than currency and collectibles coins can also be crafted into jewelry such as rings, belts, necklaces, earrings, and other forms. i myself don't appreciate seeing coins in this state but it is interesting to see what other people, besides for collectors use old coins for. looking through different coin sellers' items i have noticed many holed coins and the main reason for these holes is in fact for the use of jewelry mainly necklaces (stringing a thread through the hole). there may be other reasons for making a hole in a coin but that is the biggest one i have seen.