Unless you’re an unskilled illegal daily laborer, I can’t think of any employer who pays staff in cash. So people need a bank account, which means banks already have all your info. Add a driver’s license, gov’t health card, and passport and your whole identity is out there already.
Life is too short to worry about big brother and what if. It’s going back to living off the land or going forward and digital. Technology fails; money can be counterfeit. The Chinese are so good at counterfeiting gold coins (Kruger Rand) that some gold traders/jewelers refuse to accept gold coins. There’s risk everywhere. Is there social injustice, sure, but going back to cash is also not the solution. I’m not willing to pay a higher price at a SME/ Mom&Pop store if I can find it cheaper online.