System-designers benefit from standardized communication interfaces because of simplified integration of devices. The more is standardized, the easier is the system integration. On the other hand, any standardization limits the design freedom.
The CAN physical layer and data link layer protocol was originally developed for use as in-vehicle network for passenger cars. The CAN-based higher-layer protocols define how to use 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.