I did this when I was in Japan. I didn't want to jump through all their ridiculous hoops to get tap to pay to work, so I just threw my NFC debit card into my case and called it a day. Worked 90% of the time.

Just get a case with a card holder on the back, tap away

Your payment processor and creditor are probably also selling your info btw. If you use a service like Google Pay or Samsung Pay there's a layer of anonymity between you and the merchant at a minimum. Google has an incentive to monetize your data, but they for sure don't sell it. Companies pay them to advertise to certain demographics and geozones, but parting with that info would make them obsolete in a heartbeat. That's the strategy nowadays at least. Hoard the data and tightly control access to it. Last time I checked(it's been a few years), only like 8 people at Google even had the ability to decrypt user data with master keys to comply with lawful orders given by courts, and even then they had a good track record of denying subpoenas due to an unreasonable request for mass amounts of user data outside of specific timelines or even data on people who were within a geofence at the time of a crime. It's why there moving your maps timeline away from their severs and onto the device. I'm all for giving companies some shit where they deserve it, but in my opinion this kind of stuff gets blown out of proportion and parroted everywhere without much explanation.