I fail to see when/why this would be required, other than cases where a user forgets the password and doesn't have a back up..
You've just explained when/why it would be required.
I receive a lot of password protected documents regularly - bills from utility companies, bank and credit card statements. It's a pain to input the password every time. So I created this software to remove the passwords from a bunch of documents at once. Others like me might find it useful.