They have your spending habit! that's the data they sell to biggies like Google, Amazon and Facebook so that these biggies can serve you advertisements that matches your spending habit. So assume if you are a frequent user of Uber Eats, you will be served with ads from local restaurants and the offers you can get if you want to order food from them. Now let's assume a competitor of Uber Eats has started their operations in your country, so their advertising will be served to you over anyone else because you have shown a steady spend in Uber Eats. Data monetization is a big business which doesn't really cause a severe privacy risk but it really helps in serving right content to the right audience. Anyone working in Digital marketing field, knows that!
Very good!
You know something, I'm really happy with that!
Let ^$%^%$ google know that I don't like fast food so they can shove down their ass all the recommendations from McDonald's or KFC or Pizzahut and highlight normal restaurants when I search on a map for the place to eat. I love to actually have results from Asics or Mizuno when I search sports shoes and not some other crap like a fake 1000$ pair of Balmain shoes in the first results.
Again, they know my favorite brands, why should I give a damn if they recommend stuff that I would have bought, either way, If I'm unhappy with those I would search for something else till I find something I like, isn't that how everyone chooses what to buy?
What I don't want others to know is, as an example, for the pizza guy to realize that I have 10 bitcoins in the wallet from which I paid the pizza and I tipped him.
Just how I wouldn't go to the door with a briefcase full of money, grab a ten bill and give it to him, making sure he realizes there is well over 100k there in cash and I'm completely drunk and home alone.
That's why as strange as it might seem I'm happy to use both mixers and cards depending on the situation for safety rather than cash.
There is much-needed privacy, there is common sense, and there is paranoia.
This!
Although you're not completely right, since the times have change. 20 years ago it was considered safe to drink from the river; today even tap water is avoided in many places. Not long ago there were the phone books, indeed; now people keep databases with people's data and impersonate or try to scam them. Times have change, and not for the good. So people have to be a bit more careful. Not paranoid, still careful.
I don't know where you live but I wouldn't have drunk water from the river flowing by our village even 40 years ago.
That aside, being careful and using common sense will save you from far more trouble than not putting your family name on the door and making me ring all your neighbors to find out which is your apartment when you're a moron and you've put your phone on silent and you don't know I'm calling you.
A scammer can know your name your address your height and zodiac sign, that doesn't mean suddenly it makes sense to send 10 000 euros to a bank in Seychelles to inherit a diamond mine in Angola from your uncle you never met.