Answer:
Religion is directly tied to major world events and shapes the cultural landscape of entire continents. For example, Confucianism is the reason why, for a while, china was so safe you could leave doors open and be secure (i digress, yes Confucianism is a belief system more than a 'religion' but it has the same impact historically). The conquests and colonization of many countries by Europeans were enabled by spreading Christianity. The many phrases/references we use to this day that are rooted in religious text, 'god be with ye -> goodbye' 'oh my god' 'the prodigal son'. Religions are just large, organised folklore, it was the explanations we used to explain and put order to the world without modern science. So yeah, history has to teach us religions, not for anything else except it being so impactful and universal.