Sure, that ad (or marketing package) may look stunningly beautiful. The writing may flow and captivate you. And you may get a lot of compliments from people who tell you how much they enjoyed reading it.
But thousands or millions of dollars get poured into glossy advertising materials that don't actually do what they're supposed to do: sell.
Good copywriting focuses on that ubiquitous what's-in-it-for-me factor for your customer. Looking good can be important - but it still comes second. Marketing materials which immediately address your audience's needs will sell better than beautiful, expensive packaging which doesn't tap into your audience's desires.
Never mind how impressed others - or you - are by the marketing materials, or how glossy they are. Here's the litmus test. Ask those who are most likely to buy your product (based on their own needs): would you actually buy that product based on the materials? Why or why not?
If they tell you that it looked great, or that they really enjoyed it, but that they couldn't easily see what they personally stood to gain from buying your product - it's back to the drawing board for everyone.