Ok, it sounded like you needed to manually open it outside. I agree it's not perfect and can be improved , but it still works without needing to click too often.
It even says that's first class (called Senator at Lufthansa that time), so that flight might still cost 10 Grand today.
One really crazy thing I had I my life was being upgraded to first class in a Lufthansa flight to South America in the 90s. Afterwards I checked, the price would have been around 13k German Marks (adjusting 90s DM for inflation that's about the same in Euro today)
The first thing after boarding was being handed a glass of good French champagne, and serving beer from a barrel shaped contraption wouldn't have been "out there".
Edit: Oh looking at the picture again, that's really not a wooden beer barrel but some kind of barrel shaped container with a lid on top maybe containing a 5 liter pressurized can or so.
Edit2: Damn, I'm down a rabbit hole. Asking chatgpt it said small keg systems were in fact used in airplanes and trains in the 60s, closed system (not dependent on air pressure), driven by CO2 cartridges.
That's great news for Trump. Nothing will stabilize his regime more than having a really bad (TM) enemy.
Sorry for the cynicism.