Besides the "no" marks and the numbers -- do the shapes mean something outside of simply marking someone?

For example, I often mark the healer with a shape so that when I'm getting focused, I can find them quickly amid that bright blue background. I don't see well, so it's much easier for me to find, say, a circle, versus a tiny icon of a staff beside their name.

But oftentimes they remove it, and I cannot tell them that it helps me greatly. After reading the "hello-means-burst" thread, I started to wonder if shapes mean something else, and would appreciate if anyone could enlighten me if that's the case!