Accuracy is the first and foremost reason the industry has moved over to computer-aided machining. As we all know, computers can operate faster and more accurately than humans. For this reason, CNC machining manufactures large numbers of parts with precise accuracy each time. Additionally, we take human error out of the equation.
Another great reason to use precision machining over traditional methods is that it takes less staffing to get the same amount of work done. Manual operators take longer to do the job and may not do the job as efficiently as a computer. One person overseeing operations can do the equivalent of multiple operators on lathes, grinders, drill press, routers, milling machines, and cutting & sharpeners. Less workforce means less overhead and, therefore, lower prices.