See, that's why I don't see it. Almost nobody pays with cash anymore and less and less, because they see it as a joke to go to the ATM to withdraw cash when they can pay with their mobile or smartwatch while sending a Whattsapp or looking at an Instagram notification. Only the few who are privacy conscious and don't want CBDCs shoved up our asses continue to pay mostly with cash. But there are fewer and fewer of us.

Mass adoption is not going to come by adopting a forced intermediate step. To which we should add that if you pay with cash you don't have tax problems.  If you buy Bitcoin and when you go to pay it has gone up 0.05% you will have to report that payment in an income tax return for capital gains tax, and it already implies having to install software that tracks all transactions because keeping track of all small payments yourself is not feasible.