What's the difference between hand-drawn effect and computer drawing?

Hand-drawing and computer drawing are both expressions of designers' creative design concepts, and hand-drawing is the fastest expression form. The biggest advantage is that it can inspire designers, vivid and suitable for creativity. While computer drawing is more real and accurate, but it is slow and needs to be revised repeatedly, which is not suitable for creativity, but both are very important.

The capital art instructor once told me that an excellent designer should have the ability of hand drawing and be proficient in using 3Dmax rendering software, which can cooperate with each other to achieve the best results.