Cookout style reception?

A wedding I went to had the reception at a restaraunt about250_+ people or more after that was over we were invited to their home where they had tents set up in their big yard caterers waiters,,waitresses bartenders they had all kinds of steaks seafood and ham and you name it they had it I dont know why they would want to fit the bill for the restaraunt when the after party would have been sufficient .