The word ritual is orthogonal to how much is known about the usage. "Ritual" is just a way to describe objects that have some higher purpose, beyond any mundane and utilitarian purposes their basic form might serve. The textbook example is a thurible, the censer on a chain used in churches. They're not used because anyone specifically wants a lot of smoke in the air (a fog machine would do just fine) or because swinging them is fun, but rather because there's a higher ritual purpose being served by those particular objects being used in those particular ways.
It's like calling an object rugged or utilitarian. It's not a statement on what you know about the object's specific purpose, but rather an adjective describing something else entirely.
Hmm, isn't rugged strongly associated with the purpose of something? It's like "military-grade", it means it's designed to stand up to heavy usage in bad conditions.
It's not indicative of the specific purpose of something. You can have a rugged backpack, a rugged water bottle, and a rugged vehicle without any of them sharing the same purpose to you.
It sounds like it means religious, but it's more general than that.