Actually, all the features are valuable. The product gives deep insight into a z/OS operating system by means of many powerful commands, each of which provides information within seconds. By contrast, using normal system commands would take minutes, or sometimes even hours, to get similar information, if at all. Similarly, there are many powerful commands for modifying a z/OS operating system.
I can emphasize this with the following examples:
1. Instead of using z/OS system commands on a system console in order to get some information from the system or to modify the system, you can use CA SYSVIEW commands to do exactly the same. Compared to a system console these commands provide a tremendously more user-friendly interface to the system and the output is being displayed much more clearly arranged and accessible than console output. This means much more efficiency, e.g. for system operators.
A specific example of this is all the Dynamic Linklist commands you can use to display and modify the MVS linklist concatenation.
2. There are a lot of commands providing system information as well as system modification for which there is no similar native support from z/OS, especially in a case of emergency. This means that, without a product like CA SYSVIEW, you either had to write your own programs providing such information/modification or you even had no chance at all to deal with such a situation. This means high productivity, e.g. for system programmers.
A specific sample for this is the ACTIVITY command with all its line commands you can use to display and modify all running address spaces in various ways, e.g. displaying allocated data sets, active enqueues, task structure, canceling address spaces of even individual tasks.