I was tempted by the outrageous electricity prices a year or two ago.
But then I swapped to Agile Octopus which pretty much halved my bills and made it not really worth doing. I work from home most of the time anyway, so my usage is spread over the day.
Yup that's the free market , if someone can see a business case in operating a big battery by taking money to use the excess power and then again taking money to sell it back when needed everyone will be happy. Of course doing that will reduce the price difference