So I suppose I put it to you that there is something special about the IOUs created by banks - they are legally allowed to used.

Even if everyone agreed to use your IOU from the article the tax office is going to have quite a bit to say on the subject and probably start launching audits. And if the IOU start getting traction they are likely to trigger police raids and maybe a legislative response (look at how Facebook dropped their Libra for example). That seems substantially different from the IOUs the banks can create.

I wouldn't use bank-issued IOUs if I thought I had a choice. I'm pretty sure I'm forced to by government policy.