To add a bit more about collecting: for each boarding pass you can choose two cards from the following: 1) departure city, 2) destination city, 3) operating airline, 4) aircraft type.

On the redemption side, cards and only be used once towards achieving a collection. You can assign a card to a collection and remove it, but once you submit the collection for the reward, the cards are removed.

Collections typically require unique cards of one type (cities, airlines, aircraft), a mixture of unique cards or any cards of one type or any type.

In my view the collection "Largest of the World" is the most difficult one as it requires Tokyo, Delhi, Shanghai, Sao Paolo and Mexico City. I have one of these cities so far. The reward for this is a business class lounge voucher, which is useless to me.

The Lufthansa Group is the one I am targeting - it gives you a voucher. Strangely, I have all of the more exotic brands, just need to get Brussels Airlines and Austrian. That nets you an eVoucher reward.

To be honest, I think this will truly concentrate on gamification and the rewards long-term will be more geared towards that. For some reason I highly doubt that the Senator status reward will ever actually be made available as that has real costs associated with it to LH and Co.