I've recently ordered this card via groupon and when I tried to book a hotel I got the same problem as 'rudasvine'.
Nevertheless I still got 2 offers from other hotels where the card and the discount was valid. With some catches:
- Only the best/expensive rooms were available for discount.
- Breakfast and city tax was not included so they charged full price
So summing all the extras I came almost to the same price as the first hotel without discount, so I ended up not using the card.
All in all, I guess that by searching in booking sites on the web you can actually get better deals than with the card, so the card is not that great as initially it seems. If you can order it with groupon you might once use the card and get even with the price. For sure, not worth the full price of the card.
Also take a look at this thread:
The Reoccurring Abo Trap