Spending money on illegal things, is illegal. Spending money on dubious things, is not. I'm sure crypto exchanges and the like are illegal in some parts of the

Spending money on illegal things, is illegal. Spending money on dubious things, is not. I'm sure crypto exchanges and the like are illegal in some parts of the world. But it isn't clear to me whether that's the case in the UK. The argument here, presumably, is that banks shouldn't have a policing function. You can choose to (dis)agree with that, but it's a valid argument.