This English major is proud that she actually understood (most of) this conversation.

My take on it is that it might be worthwhile to discuss this as a "By the way, you might want to know that...but in fact, you should do your problems as you have been taught...", but perhaps only at an older age or with math-gifted kids.

Interestingly, one concept my normally math-savvy DD has had trouble with is rounding.