I had a similar experience at LAX boarding a BA flight back to Heathrow in March, so it's not a Schengen thing.
On arriving home I did some digging (Google) and found that BA are trialling a new facial recognition system to match the person at the gate with their photo on record, e.g. passport, visa application or immigration photo. BA claim that the system allows them to board appreciably quicker.
I presume LH are introducing the same system at Munich.