The simple reason for this is, to protect you lien rights in the event you do not get paid. However, the Notice to Owner lets the owner know who is working on the  property and, therefore, who could potentially lien the project if they do not get paid.    Now this happens that the owner pays the general contractor but the general contractor does not pay the money to the sub contractor and suppliers . If this happens the sub contractor and suppliers, could lien the project. Please check with your Attorney.