Upvote:7
London-Berlin is a very short trip, a return is 1162 miles, for example status Lufthansa starts at 35 k and there aren't a lot of useful perks at that level, perhaps more luggage. Redemption requires a real lot of miles:
taxes, fees and charges are not included in the mileage information. On European flights these can be settled with 18,000 miles.
Look here miles-and-more.com for the redemption chart. Say, you want to fly in comfort to the USA? That'll be 105 000 points or 90 such trips.
I would forget perks and just go for whoever the cheapest flight you can find.