Ever since I was a little child, I carry a pencil and a piece of notebook everywhere I go, so that I can sketch anywhere, anytime. As a BArch holder myself I believe in the power of sketching as an excellent way to quickly explore concepts or illustrate your design in an imaginative way. There is no one correct way to convey an architectural idea. The culture of the architectural / design practice should be shaping the type, style, character and quality of the illustration. But on the other hand, an agency or an investor would be focusing more on their target audience and ways of better promoting their project which might lead to trending presentation styles.