As a Graphic Designer, It's nice to see that you didn't dumb down our craft as "icing on the cake" as it is often referred to. But I do have a bit of an issue with this statement:

"Yes, a designer gives your application or website an air of clean, credible professionalism, but a well drawn anything does little to make your product easier to use."

Actually, a well (graphically) designed interface does a lot to make your product easier to use. Graphic Designers use design principles like contrast, alignment, repetition, proximity, and hierarchy to help users understand how an interface functions. That certainly effects usability.