You are poorly duplicating a password manager, which is an encrypted DB of passwords plus some UX goodness (autotype, file storage, notes, URLs, folders etc)
Simplicity is good. He knows how his system works, and can extract passwords even if the password manager company goes out of business and the program would no longer work with OS/hardware update. Using a very simple (~1000 lines of code) open source cross-platform tool and plain text is future-proof.