Signal? Protonmail? Personal safes? Https? Car window tinting/privacy films? Government mints? What reason is there to use cash today except to engage in crime?
If cash, tobacco, or motorcycles were in invented this century they'd have been outlawed. Digital encryption barely squeeked through due to popping up before 9/11.
Digital encryption was heavily restricted (at least in the US) until the 1990s. Its genesis during the Cold War likely played a part in that, which may be to your point.
Hmm plenty of people on low incomes or in market trades stunt have been accounts. Plenty of lie income people can't get credit cards. Plenty of people simply object to being forced to use a system that can and had refused to hand over their own cash on a whim (see Lebanon recently). So yeah, there are lots of reasons.