Paying extra virtually guarantees it will go through, which makes your perception of the message's delivery equivalent to a regular email. But the other person

Paying extra virtually guarantees it will go through, which makes your perception of the message's delivery equivalent to a regular email. But the other person doesn't know that you know that they know, while you simply know that they know. This is as explicitly as I can articulate it. What you're avoiding is them knowing you know they know. Make sense?