By definition, actuators either move things or stop them. In industrial design and other heavy-duty applications, actuators — or cylinders — provide the driving force that moves (or holds) machinery components. You may ask, "Should I choose pneumatic cylinders for my design or some other type? Well, that depends on what you need to move, in what way, and under what conditions.
Pneumatic cylinders are powered by compressed air. But cylinders can also be powered by pressurized fluid (hydraulic), by electricity, or by hand (mechanical). For obvious practicality reasons, we can rule out hand-cranked cylinders for industrial applications.