In order to make the drywall boarding give a clean look taping is done. Once the board is installed the joints and screws where the board is hung should look clean. In order to get that done taping is done to give a finished look to the drywall.
If there is any extra material from boarding is to be removed and a clean looks need to be provided it’s all done in taping. It’s not possible to give a professional and clean look to your drywall without taping.