It depends. If you can actually draw (which you can, I know) sometimes what you can do by hand, beats what can be done on computer. On the other hand, if you're using a drawing tablet, then you can achieve hand-drawn work straight into a computer as a work-around.
In the past, I've tried to create some semi-realistic maps with 3D apps. The problem is trying to apply a complex texture after creating a complex 3D model is terribly time-consuming. Sometimes the kind of detail I want, I can do infinitely faster by hand than trying to do that in 3D.
For those who aren't artists, hand-drawing is out of the question. So if you can draw, why avoid it? It depends on the style you want and the results you need...