There is a difference between selling someone something that they need but don't realize it yet vs. selling someone something that they don't need. The term "sell ice to eskimos" means you're so good at selling that you can sell someone something they don't need. You don't need that skill in a startup. Sure, good at sales, and sure, good at communicating benefits, but you don't need someone so good at sales that they can sell someone something they don't need.