No, I think the point is that you shouldn't make this distinction with respect to your budget. It's saying that if you take care of other wasteful spending, get your big wins, then plan for $500 of spending, then it doesn't matter if you make a dumb purchase. Don't feel guilty that you didn't get the best deal, don't feel guilty about the concept of a "good" or "bad" purchase, it just was within your budget, you wanted it and someone was selling it. You can't always do this comparison and avoiding dumb/wasteful decisions.

Yes, I am exaggerating a bit, but I think you missed the point.