It only stops your own device keeping a record. The website, your employer and your provider all still see it. This is privacy from the next person on your sofa.
The drawing that proves the sentence above. It is the same card that is in the book.
Think of it as
wiping your own diary, not the shop's security camera.
For example
You browse in a private window so nobody knows. Your own laptop forgets. The website, your office and your internet company all still know.
This is one card out of 275.
The hundred words you meet most are free — the whole set, animated, in one file that works with no internet.
Volume 1 has all 275 in fifteen chapters, with Staying Safe the largest chapter on purpose.