It is best to not think of it like a stock, you exchange a currency for bitcoin or vice versa. You wouldn't take 100 yuan, worth 50 dollars, into an auction house and ask for 100 dollars. Just like you aren't buying 100 sats, worth 50 cents, for 1 dollar. It is exchanged not bought. I don't know many currency traders making any money from trading currencies. That isn't bitcoins purpose.