If you are buying things with debit/credit cards the banks that issue those cards are already selling your data without your knowledge.
It is opt-out only and you have to do it in writing, there is no online hassle-free way to do it, which is on purpose. There is also no way to confirm they really stopped selling your data.
I understand that some countries allow small purchases to be made with special bitcoins made out of atoms and backed by fiat currency. I’m told that in those countries, their atom coins are ubiquitous, and, there is technology that allows mobile payments.
For example, you can purchase foodstuffs from vending machines using atom coins. The mind boggles.
My wallet could get stolen, with a fraction of my money in it. Seems more likely that bitcoins will get stolen at some point, and all your money is just gone.
Tip: Carry your atom-wallet in your front pocket. Pickpockets have a hard time with front pockets.
It is opt-out only and you have to do it in writing, there is no online hassle-free way to do it, which is on purpose. There is also no way to confirm they really stopped selling your data.