Display The total amount of the invoice in words at the bottom

Enough people have asked for the invoice total to be displayed in words that I have to ask out of sheer curiosity: What is the appeal of this? Why in the world would it be useful or desirable to do that? It’s not like it’s a cheque that needs to be protected against modification, it’s a bill. Isn’t it easier to see that I as a customer owe you $157.83 than to see that I owe you one hundred fifty-seven dollars and eighty-three cents? And it’s not like I can change the amount you expect me to pay you by changing the numbers on the invoice you sent me.

Sorry if this comes across as naïve, but I just really can’t fathom why so many people have requested this capability, and I’d like to know.