It's not ment to prove anything, as its physical size is irrelevant. The purpose of showing its physical size is to help people get a grasp of the fact that it's a huge amount of money. Like the site says, it's far too big an amount for most people to wrap their heads around at all.
PS: Anyone else when they're typing ever think of the next word they are gonna write, then type that out instead of the word they are ment to tyope, so you get the same word twice and it makes no sense? I've done it twice in recently :scratch: