A CNC (3-Axis or more) can be used for manufacturing of, electronic devices or components, custom precision parts for aircraft, nautical tools & equipment, mining equipment, construction tools & equipment, welding equipment, custom tools, cabinetry, Automotive, R&D, even Interior Decor.
2.5-D (2.5 Axis) Machines are used for, engraving materials, paper cutting machines, plotting machines, knife cutting machines (Tangential and Drag), and, some vending machines, pick and place machines for PBA construction.
More than 5 Axis include, Lathes, Robotic Arms, Some 3-D Printers like the SLS Printer (with additive abilities to help with sintering), other automation/ assembling machines.
The various industries where CNC machines are found include, aerospace, mining, R&D engineering, pulp & paper, forestry, automotive, marine transportation, oil & gas, Residential Construction, Hobby environments, Safety, and industrial manufacturing.
Often companies use CNC machines in the listed industries along with others for maintenance purposes, and/ or production purposes, a single CNC is more times than not the cornerstone of a company because of the reliability, lasting many years before requiring major work or replacement.
CNC'd devices of today include Drones, Autonomous Robots, SLS and Filament 3D-printers ,and a large number of different Cutting machines, Pick and Place Machines for building Circuits, even Vending machines are CNC'd, some of these machines do jobs humans should not and can not. Computers today are getting smaller and smaller, but still faster and faster making home hobby CNC projects more reasonably priced. An example of this miniaturisation is a micro-controller called Arduino this Re-Programmable Micro-Controller (PLC) can run a 3D-Printer with the help of your Laptop or Desktop PC.
The same Integrated Circuit that powers the Arduino also powers a micro sized Computer called the Raspberry PI; Intel even has something small, Intel competing with ARM now has a mini Computer called the Galilao, a 512MHz quad core Credit card sized computer, and yes others can be found.
Stunning advancements are taking place every day because of SMD (Surface Mount Design) Electronic Components, these Components make the computers and controllers much smaller; the ideas generated by driven people with problems, along with new technology like the 3D-Printer make new advancements available to more and more people everyday.