It looks like this is a popup for a different setting. Did you watch the video outlined in the post?

The author is arguing that such a popup should also exist when locking a vault with a PIN only.

I'm pretty sure that comes up only if you disable vault timeout entirely, not if you enable a timeout but allow unlock with PIN.

That's about as unclear as I could imagine. "If you use this option please ensure you take the appropriate precautions."

That's not what it says though. How would you phrase it? I don't think they do a great job but this is pretty hard to explain in two sentences if you're targeting a non-technical person.

"If you use this option then your passwords will not be stored securely. Any program or person that can read your files can also read your passwords."