sam4321:
This machlokes the Rosh and Rashba is misunderstood by most people. There are really two parts to the equation:
1) The bracha ‘Al Netilas/Netilat Yadayim’,
2) The act of washing your hands
The machlokes Rosh and Rashba is refering to the bracha. There are at least four reasons for washing, brought by the Magen Avraham.