How would that help? You declare your "salary" wallet, your salary flows from your day job. You run your underworld schemes in another wallet, and ne'r the two do meet.
If you buy a BMW, your identity will be noted and the transaction recorded. If you buy a bagel sandwich, the clerk will forget about you by noon the next day. So if it's small potatoes, you could be fine.
If you have a ton of cash to move, you are right- in person becomes a bad option. That's when you go back to the basics- you launder the money, like every big-time criminal in history.
"Oh, sure, some guy came in and placed a huge catering order. $10,000 worth of food. Paid in BTC. I never saw him again."