[WildHighlander57]

Paper can get lost or damaged...

[palmer]

The paper can be copied endlessly. There's no security whatsoever in the passport app or paper. It's simply a digitally signed credential and is worthless without a picture ID. That's why they say "papers please", not "paper please". The paper is worthless without the picture ID to match the name embedded into the signed credential.

This of it this way: it's a piece of paper or app with the letters "John Doe is vaccinated". The digital signature means the paper can't be altered to read "Jane Doe is vaccinated". But the paper itself can be copied, endlessly and easily by anyone.