This is only my opinion, but as Christopher mentioned, cards are to be used. I know that the Gold Monarchs are a VERY special deck of cards and i congratulate you on your good fortune in winning them. I will take it one step further and say that these beautiful works of art are not only to be used, but shared.
Now that you have opened them (which I definitely would have done, as well), they are no longer an "investment" that can be resold. So why just keep them in a drawer? Perform with them, exhibit them like fine art in a gallery. Imagine if DaVinci or Michelangelo had kept their paintings tucked away in their rooms for only them to look at and appreciate? Let these glorious cards be a beautiful medium for your magic. (Of course, I would not use them in a bar or restaurant, or have spectators shuffling them or handling them to
any significant degree). But these very special cards have a magical feeling to them, which will be conveyed to whomever you perform for. And although the presentation and touches that you personally bring to any trick or routine are certainly important, these gorgeous cards will help to showcase and enhance anything you do, much like a Stradivarius would do for a violinist at a recital.