Well understanding for a 5rh grader is different than high schooler, or graduate student, or historian. But because protestantism is such a critical historical theme in early America it makes sense to understand to some degree what those religious beliefs are. I'm not saying a fifth grader needs to dive into it, but for high schooler and college students, it's a bit more important to have a general understanding of it. But I think that understanding also extends to learning about other religions.