I remember one time in the sixth grade my friend tried to argue he was smarter than me because all of the games he played had some form of currency so he learned financial management through games. I then countered his argument by trying to argue that most of the games I played also have some form of currency. He brought up Sonic, to which I replied that in the Sonic Adventure games rings can be used as a form of currency in the Chao Garden. He didn't know how to respond to that other than bewilderment, but ever since then I have wondered if things like coins and rings really count as "money," in platformers, but I'd lean towards yes. Coins are literally used to buy things in practice.