I absolutely would oppose such a system, and if my choices were somehow limited to this or keeping bags of cash under the mattress I'd go for the cash every tim

I absolutely would oppose such a system, and if my choices were somehow limited to this or keeping bags of cash under the mattress I'd go for the cash every time. My objection is fairly simple - I value my privacy. I don't want my financial status visible to everybody, and I don't see any particular upside for me in a system that allows that.