Does the sales page needs a kickass copywriting too?

[mediadrug]

The content on your sales page, therefore, should be aimed at providing a clear example of how your product will benefit its buyers; do not simply advertise the product, tell a story that describes your customer's pain and how your product can alleviate it. Also, provide customer testimonials (accompanied by images if possible) as they are invaluable in building the credibility of your product or service.

I believe that what you are describing is for a landing page not for the sales page.