If you are trading in the futures market and you don't have inside info or are not an actual supplier of the commodity, you are the sucker.
They also allow some insights on future demand, which can help you plan production of your commodity.
The issue is that the odds aren't actually 50/50 on you buying either side of the trade; one half will look like a better deal (and given public information, it is a better deal) so you'll buy that half. Then when the market resolves, it'll turn out that insiders knew some piece of information that made the other half of the trade a better choice.
P(W | You're a sucker) = 0.5
hard to win at a game where 97% fail in the long run.