Wait! STEEM DOLLARS for Bitcoin?, Bitcoin for U.S. DOLLARS?, U.S. DOLLARS for bananas???

Is this the way this works, STEEM DOLLARS for Bitcoin, Bitcoin for U.S. DOLLARS, U.S. DOLLARS for bananas? But isn’t it better just to use US dollars to buy bananas, why the long ride? Maybe I am bananas,
but I am just saying, why?….

You tell me...