To me it’s just a proxy for the amount of economic activity in a place.

Every time I go to Melbourne airport in Australia, I’m shocked that nobody - nobody - has their laptop out. In Sydney a few people do. But go to any airport in the US and if not a majority are on laptops at least a large minority seem to be..

So yes - airpods in ears, laptops in airports, city lights at night. Just a sign of how plugged in everyone is to “something” that’s happening.

Not all activity is economic activity and not all economic activity is valuable. People outside the US aren't generally expected to work 24/7

It's totally incorrect to state that the area served by either Sydney or Melbourne airport has less economic activity than the area served by "any airport in the US", or even the vast majority of US airports, so whatever laptops-at-airport (and I suppose airpods-in-ears) is a proxy for it sure isn't economic activity.