Yeah, I'm sure CC users had their doubts too. They had numbers too.

Guessing a number is not theft. But if I have purchasing power in my hands and you take it from me, thats theft. If you think it is not, try it, tell the police and lets see where you end up after the courts take a look. No need to trust me: https://www.mdpi.com/2075-471X/12/2/33