It's interesting to hear that your drawings make teaching easier but drawings are also important to express feelings. Strange I haven't heard anyone mention that.
If you can't talk you can still make a drawing and there's no need to draw very well for that.
Teachers even label children because of what they draw and let parents show up. An interesting thing about drawings is also that everyone sees what he likes/wants to see influenced by?

It reminds me of a drawing a child made about the vacation. The teacher saw the parents and children hanging with a rope on their necks. The parents were ordered to come for a chat (or perhaps only the mother) who smiled and said the child had drawn very well what they did in their past vacation.the family had gone snorkelling in the sea.

I am still curious how that teacher felt. It also reminds me of psychiatrists asking patients what they see if pictures with dots on it are shown...