Think about it! Keychains, whether PVC or Metal, are more than useful, they are essential to our day to day life. Every one use keys, for their house, car, motorcycle, safebox, padlock, and so on. Keychains have two main functions: to join together a set of keys and to be visually attractive for us to not loose them or to find them faster.
We carry them anywere. No matter if it is a simple walk, we can leave wallet and cellphone at home, but never the keys, or we will be lost. Moreover, the keys have a powerful meaning as a symbol. Have you heard about “the key to the future”, “the key of success”, “the key of a romantic relationship”, every thing have a key!
…at least metaphorically. When you giveaway a shirt, is useful, but it is just a shirt, when you giveaway a snapback is usefull, but it’s just a cap.
The same thing happens with classic promotional products such as pens and cups or jars. Nevertheless, when you giveaway a keychain you are giving a way not only a usefull thing but also an extraordinary symbol.