Its not cheaper or more expensive, it's required. You can't process things very well without uniformity and accuracy, that is why so much effort in machinery is geared toward consistent return.
It actually helps to work with some machinery to understand this, when you chase out the demons from your processing you start to realize that machine precision is a sliding scale (not a given) and that consistency and accuracy is an important thing for it all to work well.
It's similar in some ways but it's a totally different animal than making accurate hand tool work with some overlap. That is why there are so many processes which are better done by hand, and so many better done by machine....blind dados, for example.
Bumbling forward into the unknown.