Consider a coronation. From the standpoint of science, nothing happens; and yet, the course of the world may change because of it.
A coronation has its own rules which must be performed correctly. “Silly” you say? I remind you that President Obama had a “redo” of his oath of office because it wasn’t done correctly. If this is just pretentious nonsense, then why bother?
The reason is that coronations and oaths of office have a significance beyond physics. It’s the same for religious practices. To do a DNA test on a communion wafer is to fall prey to a category mistake and to totally misunderstand the purpose and meaning of the act.
Let’s say that you enjoy playing the cello. Realistically, the world is not significantly different after you’ve played the cello than it was before it, except perhaps that it is now thirty minutes into the future. Is there therefore no point to playing the cello?
Religious rituals serve a spiritual need within a person; they enable spatiotemporally bound people to experience transcendence. It has nothing to do with physics. To say that it “serves no purpose” only means that you are missing the point.
Whether your rituals are solitary or in groups, if you don’t have any, you are likely to be profoundly unhappy.
IMAGE SOURCE: commons.wikimedia.org/wiki/File:Charles-vii-courronement-_Panth%C3%A9on_III.jpg ATTRIBUTION: Jules Eugène Lenepveu (1819-1898) [Public domain]