Here is an example of an early encryption method still in use today.
Do you think that it isn’t useful today? What if I told you that I’ve already received letters that had been tampered with?! Yes, that’s right! In this XXI century!!! I’ve already received a letter from India that had been cut open and carefully glued back again!!! So, it’s content was read. Had it been wax sealed it wouldn’t have been possible to try to conceal the crime!!!