Ironically, an effective ban on twenty-first-century crypto might also require phasing out (or at least scaling back) the much older device of paper currency, because cash is by far the most convenient way for people to “on-ramp” funds into their digital wallets without being easily detected.1

bitcoin

What’s the Crypto Regulation Endgame? | by Kenneth Rogoff - Project Syndicate

He even wrote as much in the article:

> Ironically, an effective ban on twenty-first-century crypto might also require phasing out (or at least scaling back) the much older device of paper currency, because cash is by far the most convenient way for people to “on-ramp” funds into their digital wallets without being easily detected.1