Great point! I have lived it… just wish I would have been smart enough to post it!
Off topic: It is this sort of thinking that is systematically destroyed in our education system. Pretty much anyone here has the math skills to understand this after hearing it a time or two (or more), sitting down with someone and going over it. Very few are able to actually come up with this thought on their own even though it is pretty darned important stuff for the financial well-being of a person / family and relatively simple math.
There is also a component of being able to sleep at night… either in a knowing fashion or not. I sleep VERY WELL at night, knowing I am using a number of different methods of leverage. Others may not be able to sleep at night until their mortgage is paid off and all credit card bills are paid as soon as the statement posts. I think a lot of those folks don’t really understand the math. My $0.02 and worth at least half that much.