Great! So, do you bring your whiteboard to lecture to turn in, or take a picture of it, or just schedule time with your professor to whiteboard in front of them?

All I'm arguing for here is that UML serves the same purpose as those online homework apps. Correctly formatting your calculus homework to be accepted by that interface is as unrelated to calculus as UML mastery is to effective software design, but it resolves some of the same logistical challenges, while introducing others.

A whiteboard is just a medium to draw. Uml is a standard that says how to express certain ideas as symbols that can be drawn.

It's not clear to me what your argument is. Is it using whiteboards to draw uml instead of special uml software? If so, be prepared to take much longer to draw the diagram.

Or do you mean uml is deficient compared to free drawing of symbols on a whiteboard without a standard? If so, be prepared that nobody will completely understand your diagram without explanation