You will no longer be able to sign in to YouTube without a Google Account. If you do not want to link this YouTube account, you can fuck off.

Please note: If you link your YouTube Account to a Gmail Account you will not be able to change the email account with which your YouTube Account is associated/linked in the future. When you link a YouTube Account to a Gmail Account the Accounts are permanently linked and this cannot be undone.

If you link your YouTube Account to any other type of email account, you can choose to link to a different Google Account later.