PGP = Pretty Good Privacy. It’s both a company and the original product released by Phil Zimmerman that has since been mostly replaced by Gnu Privacy Guard (GPG).

These products create paired secret keys using the ciphers of your choice. You make the public key available to the public and keep the private key for yourself.

Then, you can either sign or encrypt some content with your private key, and anyone with your public key can validate that it was you who signed or encrypted the file.

You can also use someone else’s public key to encrypt a file, and then only the holder of the paired private key can decrypt it. And they can use your public key to validate that it was you who encrypted it.

Email addresses are optional, but can be embedded in the keypair. This means that someone else can verify that that address is linked with the identity of that keyholder, which assists in getting encrypted content to the right recipient, validates any signed/encrypted email sent from that address, and provides a memorable link to the public key’s owner.

I mean you can make one without the metadata or phony metadata, it's primarily used by software to validate you. It's not like it validates any of the info. You can put [email protected] as your email of you want, good enough.The general idea is that a PGP key is an identity, not just a key pair. There's plenty of non-PGP ways to make key pairs.

It's useful when other people look through their keyring, so I can easily find which key I'm looking for. People don't usually go find your key every time you want to send a message, they import your key then specify the ID or email of the key to use which is usually automatic based on who you're emailing. And then when you message back, they want their messaging client to be able to look up your key and validate it automatically. I'm not going to go browse my files to find your key again to verify every single one of your messages. And I'll be messaging you at some email address or other identifier somewhere anyway, so the key ends up tied to a form of identity regardless.