In my opinion targeted promotions are not likely to have any significant impact to the bottom line. The number of invitees is often so limited, further reduced by the response rate, that it won't kick in any big numbers. You need a universal offer, like a huge public sale, or double base miles (like twice for Delta in 2001) to attract enough people to make a difference.

More likely it's just testing how well their marketing is doing (what the response rate is).

Jeff