Your sales people are not going to spend ages finding out what a customer should do with your API. If they are daunted with a very generic, technical or non-existing description of what the benefits, use cases or in broad terms value of the API is for them, they just won't care. They will rather skip talking about the API at all or always drag the developers, product managers or who ever they can get their hands on to the sales meetings to explain things.
But the real point is, the API shouldn't need hours of explaining. It should just be there, and a person (developer, architect, business developer etc.) interested in solving a specific problem or completing a task would just find it and take it into use.