The problem with articles like this is that it will be true until it’s not. At some point I believe it’s inevitable that advances in battery tech will mean background running apps will become a thing and at that point the article will be the one selling myths. Also, has anyone ever quantified the extra power impost of closing and reopening an app vs just leaving it alone?

Except if you have different permissions for an app while it's running and in the background.

There’s still someone who do it?! I thought this myth was debunked years ago bb

Except if you happen to have used multiple camera apps. Closing those deliberately can avoid some unintentional behaviours, particularly if one of the apps is specifically selecting a single camera and the other is the built in camera app.

I suspect the same applies for certain connected devices.