I'm pretty sure the original form of that thing was about interest, showing how a small amount of money can grow into a large amount. Guess it has been warped over the years since I first heard it.Yeah, I assumed it had something to do with interest.
I looked it up assuming the catch would be something like waiting so many years with interest.
Instead there's a bunch of variations of the above.
Like save a penny a day, 2, the next, etc.
Save a dollar a week, 2 the next, etc.