I feel it depends on whether its Art or CG. If the final output is Art then anything goes, use whatever you need to get your minds image on the monitor. My art instructors hammered this concept into my head many years ago, Art is freedom, freedom to choose your tools and techniques as you see fit, and to use as you see fit. CG is a pure render untouched, usually as a means of displaying a model youve created, more a presentation of see what i built, simple mechanics with no soul. My 2 cents. :-)