The goal of the service catalog cli (svcat) is to reduce the learning curve for developers and follow precedent set by kubectl when reasonable so that "finger memory" built-up from using kubectl translates to being able to use svcat without reading the help text much.
It isn't intended to be a replacement for kubectl, and instead users will jump back and forth between kubectl and svcat. As a plugin, it reinforces the mental model that svcat conforms to the way kubectl works, and makes the switch between the two less noticeable.