You bring up another good point and that is that we spend about 15% more if we pay by card vs cash. The feeling of cash in our hand leaving it is much more tactile and emotional than swiping (ohh I'm old. inserting, tapping) the card. No wonder they want to go cash less and of course the side affect is that they would know all that you buy.What does it cost, and what do I get in return? Not just in terms of cash, but also my data, which I value far higher than those trying to extract it from me. This is pretty much what my life choices boil down to.
I'm happy to have a microwave and washing machine amongst my appliances. They make my life easier. I don't have any smart home tech though, as they are far too costly due to the continual "data payments". I don't have any streaming services or digital news subscriptions for the same reason.
Cash payments are relatively easy to determine if I am getting good value. It's less easy when paying with personal privacy. I look first to see if there is a cash alternative before making digital (cash or data) payments.
Example:
A low cost fountain pen gives me a lot of enjoyable writing, for a modest outlay. The cash price of fuelling said pen (ink prices) is ridiculously low per miles written, but as I can't buy in person, there are data costs too. However, as they are so few and far between (due to how long a bottle of ink lasts), I'm happy to pay that cost. I'd prefer to give that little bit of data to an independednt though, rather than the likes of Amazon. Talking about said pen on Facebook has a massively higher data cost than I am prepared to pay, so I won't have a Facebook account.