Not sure how being prehistoric makes it more likely to be for ritualistic purposes Juamei. We have absolutely no idea what its use would have been (yet) or whether they carried out ritualistic practises anyway, it's all speculation based on what they presumed took place. Ceremonial, another overused word, is certain to appear at some time as well.
One could claim that just sitting down every day to have our meals is a ritual practise and there would be no denying that, but I don't think that's the type of ritual they are referring to here.