What is the reason for using these git commands prior to git init? git config --global user.email and user.name

a name and an email address are associated with each commit. It is really just a label and is convenient to see the name and the email of someone who made the commit.

It is not required though, you can simply put a blank for those if you wanted:

git config --global user.name ""
git config --global user.email ""

you may not want your name or email exposed.

according to the git documentation

Git comes with a tool called git config that lets you get and set configuration variables that control all aspects of how Git looks and operates. These variables can be stored in three different places:

/etc/gitconfig file: Contains values for every user on the system and all their repositories. If you pass the option --system to git config, it reads and writes from this file specifically.

~/.gitconfig or ~/.config/git/config file: Specific to your user. You can make Git read and write to this file specifically by passing the --global option.

so by passing in the global flag, you set those variables for your user account, this way no matter which repo on your system you are in, the variables will have the same value everywhere.