I'm not worried that "somebody's watching me" and my spending. You can't order online with cash, and I buy a lot online. (that was the reason I got my first credit card years ago) Though I do remember a few times mailing a check for a purchase online. I still have a checkbook for the maybe once-a-year I need it for something. The last two times I needed it were to void a check to set up direct deposits.
I like getting the credit card receipt with my purchases, I put it in my wallet and record it (formerly in checkbook, now in Excel) when I hvae time, that's where I balance my bank statement.
Recently i got a Paypal Business Mastercard, and they offered me 10% cash back for the first three months, so I've been using it almost exclusively instead of my bank's ATM/Debit Visa card. I probably should have seen this coming, but it has the great benefit of Paypal immediately emailing me a receipt when I make a purchase. I still get receipts, but it's a nice double-check in case I miss a receipt. I was going to just go back to my Debit card after 3 months, but I really like getting email receipts of use so I may just continue to use it. (the paypal card also has contactless payment that I've been experimenting with)
I guess I view the people that are insisting on using cash as unnecessarily paranoid. "But they're tracking you!" So what? So's Google, Facebook, Microsoft, the Feds, the IRS, everyone's tracking everyone. So what? It's nor hurting me. You can't avoid it all anyway, it's just a waste of time to try, and will ultimately only result in inconvenience to yourself. (and you may seriously regret it the day you need credit to do something like buy a house or car!!)