The trade you're making by being a Griddy customer has essentially unlimited downside risk though. Retail investors can make those types of trades in securities, but they are heavily regulated and it is made very clear just how risky they are. It's also possible for your broker to liquidate your positions very quickly if they margin call you, so they can protect themselves from that downside to an extent. Griddy can't cut off your power in an instant when the spot price jumps.

If a traditional electricity supplier tried to buy all their electricity daily at the spot price and not hedge against any risk, they would quickly go bust. So why is it sensible for consumers to be allowed to do that? Some businesses may buy their energy at wholesale prices through their supplier, say an aluminium smelting factory. But those businesses will have full time traders who are also buying insurance/derivatives to protect against volatility in the market. Consumers should insure themselves against that risk too, by using a more traditional energy supply contract.