Re: I wonder....
Lets look at the worst cases and see if all that effort is worth it:
Store cards - Tesco tries to sell you other stuff and annoys you with adverts.
Amazon - Amazon tries to sell you stuff and annoys you with adverts - possibly one of those adverts shows a present you were buying as a surprise. More annoyance.
Ebay - It goes wrong and things you don't want in your history appear in your history. Worst case is similar to amazon. Unless you're buying illegal stuff then you go to prison and too right.
Google - Google knows where you are and pesters you with ads, etc....
So the worst here is, depending on what you do, either mild annoyance or prison.
As I'll never go to prison for buying tat on EBay then I take the risks and don't worry.
Can anybody else show me any worse results. I'm still waiting for a realistic example of a bad outcome that doesn't rely on paranoia of accepting all the defaults in Windows 10