You are using/losing 40k miles. If they are about to expire unused, fair enough. But I know of many people that have gifted such cards to people who use them maybe twice. Also it should be added that according to TK's rules, unless it has changed (which I doubt) you can only gift someone a Gold Card once in a Lifetime. Meaning that if you give one to your spouse, and then in 3,4,10 years time, you want to give it to the same person again, they will not let you do that.