Well, true, past performance is no guarantee of future performance.
I'd be interested to know what guarantees are in place to ensure the money is paid back, and how much of that £200/person is actually returned to the exchequer, presumably adjusted for inflation and to include interest.
I do know that effectively, energy suppliers now have £200/person they didn't have before, so charitably it's a very cheap, subsidized loan. That they're temporarily transferring the cash to their customers is a bit of a feint, since the customers can only give them the money back.