Exactly. The house hold gods' main purpose was to protect the house and in order to do so they needed to be shown the proper respect. I think the main idea was to keep alive the respect for own culture and ancestors (as far as I know something similar can be seen in chinese culture or at the american-indian natives). The funny thing is that these rituals weren't able to prevent a certain character to make his horse a senator and responsible for all the grains in Rome. As we know the personage was Caligula and the horse was Incitatus :P. And this is not the funniest part. The thing is that a culture whos ancestors were deified in order to preserve that culture gave birth to characters like Caligula, Nero and others that became "gods" themselves "before time". And this "gods" contributed greatly to the downfall of Rome. Today's paradox it's tomorrows banality someone once said.