Let's be real here: You, I, and most of the people in this thread talking about privacy concerns when it comes to cash and what not are playing pretend. I say this because the odds are we have a significant amount of our money invested in some form of digital investment. Whether it's stocks, certificates, money sitting in a bank account. The nature of cash means it scales up poorly; and the nature of holding cash means you are literally losing money year over year thanks to inflation. The system is built to encourage this.
If the government wanted to freeze your accounts and take most of your net worth, they can. And while cash transactions can be secure, in our day to day life where our transactions are done cash is not meaningfully adding anything to our privacy. To actually achieve any sort of privacy with cash involves operating purely with cash: That means no bank accounts, no investments, you are paid directly by your workplace with cash etc.
That's why again, cash will not protect you. It will not protect most of the people here acting like it will.