When you go on vacation, you don’t want to keep all of your cash in one location, like your wallet, in case someone steals it. It’s best to put a few bills in your wallet, some in your suitcase, and maybe even a few in your bra or shoe.
Also, you can put your cash in unpredictable places like a suntan lotion battle or deodorant. In this way, you prevent to be pickpocketed.