Different companies see the benefits of CNC somewhat differently. I'll express the answer to this question from the viewpoint of a product-producing company. Consistency of workpieces produced - Since a CNC machine executes a program, and it will do so in exactly the same fashion time and time again, the consistency of workpieces produced is much better than workpieces run on conventional machine tools. Faster workpiece machining - Since current model CNC machine tools are guarded (splash guards, windows, etc.) in a much better manner than most conventional machine tools, users can apply the most efficient cutting conditions to attain the best cycle times. Manual machinists tend to nurse-along their machining operations to minimize the chips and coolant are constantly thrown from the work area. Lowered skill level of machinist - Though there are some misconceptions in this area (some people believe that anyone can run CNC machines without training), the level of skill required to run (but not program) a CNC machine is much lower than that required to run a conventional machine tool - especially in a production environment when the same workpiece is run over and over again. Complexity of workpieces to be machined - CNC machines can generate very complex motions, making it possible to machine shapes that cannot be generated (or are extremely difficult to generate) on conventional machine tools. Flexibility, faster turn-around, and smaller lots - Because they're programmable, a given CNC machine can be used to machine a large variety of different workpieces. Most are also designed to minimize downtime between production runs (setup time). Some conventional machines they're replacing (screw machines and transfer lines, for example) are extremely difficult to setup, making them feasible only for larger lot sizes.