I was pondering the importance of ritual, ceremony, chants, etc. My best idea is that it's to keep us on the path. Kind of like adding tinder and fuel to a fire we have started, so that it wont extinguish itself. This is also true of our sitting Zazen or meditation.
I don't think we do it out of dogmatic obligation. When we want to delve into our spirituality and the practice of Buddhism, we do things such as rituals, chants, and meditation to keep a base. The base can be seen as a foundation for living our lives or handling our affairs according to the Dharma.
My guess would be that it's the similar situation of people of other faiths going to church and the like. They go to hear the pastor's, reverend's, or priest's words to keep in touch with their faith and remind themselves of the teachings.
When we can realize the meaning of what we do and why, it gives a deeper dimension to the practice. So keep chanting, prostrating, and meditating to keep the course. :)