Don't take words literally. Instant in this context means what jawngee said, that it was so responsive to the degree that people conceived it as instant. Awesome. Layers were unlimited meaning you could add as many as you want. Undo operations were unlimited meaning you could work on it for 10 hours straight and undo to the point it was before you started working on it. I believe that's what everyone gets from these words, except you.

It's not like people will think it's unlimited for real, there's no such thing.

It seems to me you are having problems interpreting words in context.

EDIT: I mean, if he said you could have 8K undos, or 8K layers and the response time is <15ms would that make you feel better? Does it make a difference?