I suppose you could do that for complex parts, but you're still going to have to do a bunch of CAD work to fix the model afterwards. And it doesn't matter the part, I could model it up faster than someone could scan a part and repair it with surface modeling. It's just the wrong approach to...
Yeah, and modeling with surfaces is not very easy to learn. There are youtube creators that teach various software like Blender. You can download Blender for free, and watch a guy by the name of Blender Guru on youtube to learn it.
A 3d scanner won't be of much use unless you are wanting to...