Why is Writing Important?

In my career as a mechanical engineer I would say that I would not have to do much writing except for math problems and such. On the other hand, if I was to become a speaker on behalf of a particular item a crew and I have developed such as an engine I would say that I would write on the basis of a presentation. For example I would have to persuade a potential buyer into buying the engine I helped develop. I would have to explain the knowledge that I have towards the engine. I would also have to explain why my engine is better then someone else’s engine. By doing all of these things I would have the majority of my writing should be compare/contrast, persuasive pitch to buyers. Although this is probably the only type of writing I cannot imagine a mechanical engineer doing, other then problem-solving of course.