Useless Language Conventions

I learned today in Chinese class that there's a different measure word for family members than for normal things. I can understand why there might be a different one for indeterminate quantities (like sugar or snow), but I find it entirely useless to have a word that literally means the same thing as another but has to be used instead of the other in a certain context. This is why I like Lojban so much: It only has exceptions when the exceptions are meaningful. For example, the words to start a narrowing and descriptive appositive are different because those are actually different concepts and the two words provide clarity as to what is being described in the sentence. In language, it's my view that everything should be the same unless differentiation is required to display differentiation in the world.