Re: "banks telling their customers what they can and cannot buy?
"Investments may go down as well as up etc. What if someone wants to use their card to buy a load of "investment" wine?"
Let's think about that for a moment.
If the money stays within the classical financial establishment (ideally within the UK financial establishment), where's the problem, even if (especially if?) it's large quantities of money going to an organisation that isn't competing in any real way with the (UK) financial establishment?
Cryptocurrencies, on the other hand... well, I'm sure readers can work it out.
Btw, I personally wouldn't touch crypto currencies with a bargepole, but I would be very happy indeed if more people had a genuine alternative to the UK financial institutions.