Device-designers benefit from standardized communication interfaces they can use off-the-shelf hardware and software. The more is standardized, the more they can buy from third parties. Another benefit is that the device with a standardized communication interface addresses a broader market. On the other hand, any standardization limits the design freedom.
The CAN physical layers and data link layer protocol was originally developed for use as in-vehicle networks for passenger cars. The CAN-based higher-layer protocols define how to use of the CAN data link protocol for specific application requirements. Besides proprietary CAN-based higher-layer protocols, there are also several internationally standardized ones: CANopen for embedded control systems, DeviceNet for factory automation, J1939-based solutions (J1939-71, Isobus, ISO 11992, CiA 501/2) for trucks and other vehicles, ISO 15765 for passenger car diagnostics.