Your Product Owner is a fraud and should be immediately replaced if they cannot in very simple terms explain:
- why the product is being built – what value does it bring to the business in terms of ROI;
- why the product is being built – what value does it bring to the customers, why should the customers use it;
- what actions should the customers take to get any value from using the product.
Everything else is pretty much secondary. These three points, however, are non-negotiable.