Printed USD is extremely hard to trace. The US government agencies, credit card companies and banks hate it because they can't track your spending habits. Granted I don't use cash for large transactions (I usually don't carry that much cash) but for getting some last minute things at the grocery store, or fast food, or snacks at the gas station, it is great!
I like privacy coins because a random person cannot just look at my wallet address and see my balance or transactions. At least with a bank, a random person needs a warrant or court order to find out the basics of my bank account. Creating a new adress for transactions works for mining where it is easy to just redirect rigs to a new address but it is not really private, pseudonymity I believe is the term here. Unless that coin makes tracing transactions difficult and/or hides wallet balances, a new wallet address only works until you cash out, i.e. send it off to a KYC exchange, convert those coins into fiat currency, and then deposit it into your bank account or credit card. Once that wallet is associated with a fiat account or KYC account tagged to your name, anyone with the proper access can trace everything from that wallet directly to you, the transaction history, the gains or losses, when you were paid, how long you held the coins, the balances, and so on, no more privacy at all for anything associated with that wallet anymore.
