State currencies not the only game in town
I'm a member of a LETS group which has operated for 21 years. Money earned that long ago is still spendable at par with conventional UK sterling at our trading events. You don't have to waste electricity to do double entry accounting within a closed group. And if you dislike conventional currencies as value standards, do the same kind of accounting using hours or minimum wage hours as your value standard at the cost of making it marginally more difficult for account-holders doing tax returns.