I got it because of a complaint with LH. It says Dear LH passenger:

"It gives us a great pleasure to present this personal gift voucher as a gesture of our appreciation for your continued patronage. The next time you fly LH on an intercontinental route this voucher is yours to exchange against any item sold on board up to a value of 25e.
It can also be used as a partial payment for items exceeding the voucher value but it has no cash redemption value, and no credit for unused amounts.
Enjoy your inflight shopping, and thank you for choosing LH again."

Obviously, it sounds rather personal to me, but the problem is i seldom fly LH. It does not have an expiration date however so I may be able to use it in the future if i choose.