The exact same money feels easier to spend as coins than as one large bill
In studies by marketing researchers Priya Raghubir and Joydeep Srivastava, people given money in smaller denominations — coins or several small bills — spent significantly more of it than people given the identical value as one large bill. A single big bill feels like a meaningful 'whole' worth protecting, so people psychologically resist breaking it, while a pocket full of change already feels broken into spendable pieces.