Teams don't just work together magically and "organically". They're made of diverse human beings, every one of us, who come from different backgrounds with different expectations about when and what to communicate and when and what not to and around what is who's responsibility when. Different levels of experience, having worked at different places with different practices, and different preferences about how to do things. This is a recipe for a hundred miscommunications and inefficiences and misunderstandings a day.
These processes exist to surface the most important things not being surfaced, and to identify and fix problems that affect the team but which nobody is understanding in full because everyone only knows their own perspective.
Again, these aren't "rituals". They're processes that are proven because they work. Including with 5-6 engineers.