sudo is not new. sudo has been around with BSD for ten years or more.

sudo is preferrable to the root account for several reasons. In order to use root account, its password has to be known. If ten users on the system wants to be root, those ten people have to know the root password. It can easily get out of hand and get compromised.

sudo, on the other hand, is completely based on each user. You don't need to know anybody else's password. You use your password to gain root access. It's easy to give and take away root access to the users.

On a personal computer like Mac, it may not matter that much whether to use root account or sudo. sudo is still more convenient because you don't need to know extra password.