“What” to do, or what it accomplishes, and “how” to do it, or how it does it, are certainly relevant, but most critical is “why”. Why would I buy your product? Why would I buy your service? Why would I believe this or that, or why would I change my mind? Why should I support this or that? Why should I care?
Why, is what defines the purpose and desired outcome, and it’s far more critical to convey the “why” than the “what” and “how”. Why is the thing that inspires and connects with people and motivates and gets others on board. If you don’t have the “why” (or a believable why), then success will be limited, regardless of what you are selling or advocating.