The DCS is a control system used to control a physical process in business, traditionally with many control loops.
The controllers are autonomous, which keeps the cost down and reliability high. The system is monitored and adjusted remotely and keeps all controlling functions nearing the process, creating ease of monitoring and adjustments if necessary.
As processes and businesses grow larger and larger, the need for a DCS grows with it. Many processes can grow so large that controlling them without automation can become nearly impossible.
Now you might think it would be a good idea to have a human being in those places, but tell me this, are humans guided by the three laws of robotics?