Or to bring it back to the original context... Reducing volatility would be reducing the impact of bad weather on your harvest, absorbing volatility is finding someone to cover your losses. (presumably by giving up some profits on the good years. It's like a financial low pass filter)
Volatility is a natural consequence of weather, blight, etc., etc.
To reduce volatility you would need to actually stabilize the supply of onions.
What futures do is allow traders to shift risk from the future to the present. By pricing that risk, it's possible for people who depend on onions to pay a little more now in exchange for a guarantee about the future.
It's not magically going to make onions less volatile (although high risk prices can spur investment which might) but it can reduce disruptions caused by volatility.
The classic example of this is futures on jet fuel which allow airlines to weather random wars in the middle east, OPEC shenanigans, etc. Ticket prices are higher this way, but the existential threat of being forced to cancel a bunch of flights is gone.
For speculators yes. But for a farmer and the consumer of the goods they would rather lock in a margin for their goods and run their business than risk guessing what the price will be at harvest time or consumption time. It’s called hedging.
How many farmers do you imagine are in this thread?
And consumers neither lock in margins nor run a business because consumers buy at retail…
Ok charitably, maybe you use “consumer” in a special sense of businesses that consume raw materials such as owners of onion ring factories. In those cases, future prices (as opposed futures prices) are typically negotiated directly into contracts with producers of those commodities…and how many of those are in this thread?
In the vast majority of cases, futures are traded speculatively and physical delivery of goods and chattles is an extreme exception.
People are willing to lose a small but predictable amount of money to avoid occasionally and unpredictably losing a massive amount of money. The former is a loss they can plan for and absorb. The latter might kill their business.
Traders are often happy to take the other side of that trade because they can trade against many counterparties, collect a small premium from each one, and try to ensure their counterparties won’t all fail in a correlated way.
You may have liabilities or income that exist outside of financial markets e.g. if I have 500t of wheat due to be harvested I might want to hedge enough to guarantee I can pay my staff - ive locked in the price of wheat, I might make less money as a result but my risk is lower.