Thank you for posting this you are correct the fee goes to the restaurant and they use the money to pay the back of house. In my experience it is just so the restaurant can provide the same wages as before to back of house but not out of the restaurants pocket. This tends to result in people tipping less so the server directly makes less money. There is also often no accounting/oversight into how the restaurant uses the fee. If I recall correctly the city of Los Angeles is looking into the legality of how these fees are presented to the customer and the fact there is no oversight.