SSH keys are used because they are the de facto standard for git authentication - GitHub didn't invent this, this is pretty much how it is done with any remote

SSH keys are used because they are the de facto standard for git authentication - GitHub didn't invent this, this is pretty much how it is done with any remote git repo. I don't use Mac, so am not sure what applications might generate keypairs that the user would not be familiar with. But, the guide does have a step that moves existing keys to a backup folder, so they shouldn't get deleted, in any case. I'm not totally sure why they want a clean private key, and don't let the user simply copy the existing public key over if a keypair already exists.