Read the terms on the cert. As I recall they are not transferable and therefore must be used when you are staying. Now that doesn't mean you won't be able to get away with booking the room in your name, adding your wife to the rez, and then not show up. There may be some risk, but may be worth a try if you won't have any opportunity to use it yourself.

Depending upon her risk tolerance level, you might want to check out how comfortable the couch is.