It makes it fast and easy to back out if you screw anything up. Even if the data is still there, it can be complex to pull it back out and configure it the way

It makes it fast and easy to back out if you screw anything up. Even if the data is still there, it can be complex to pull it back out and configure it the way it was when you started (as the commands in this tutorial demonstrate.) So a fast, easy snapshot before executing complex commands is a smart move.