You no longer need a card (credit or Mileage) to book an etix, but such tickets can only be collected on presenting a picture ID at checkin. This prevents from someone using your identity to fly on LH/OS.

In the US you can collect such tickets at the machine by typing your name in as the gate agents and security will check your name against a picture ID. This usually does not take place on LH/OS flights, unless they suspect fraud or you are on your way to/from the US or any country that has specific immigration/visa laws that require this.