The rules set a minimum requirement. Normally there is no limit on exceeding the requierment
There is: The expenses. The "JFK intrernational" like airports is very minority.
Most (by counting, not their improtance, nor traffic or size, etc) airports are nothig more than a regularly mowed stripe of grass field framed by the required red-white marking signs (the minimum "equipment" to be officially recognized and published in maps etc).
Even not a single building, even no shed, nor "wind sock" or anything like that at all.
Then a buit less airports have just some shed nearby.
So the cost to run such airport is no more than every two weeks mow the grass andd every other year repaint the marking signs. Not that expensive to operate at all.
You can know about the existence of the airport from seeing the runways from the air, especially with the lighting on.
You would have to be a Superman or it would have to be the "Area 51 main airport" (so in the middle of dark nowhere) to spot it except being few miles away and lined up with the runway. Hypothetically possible, but exremely unlikely if you do not know about its existence from some other source.
The fact you spot it when in a landing airplane is a bit misleading - the pilots had already lined up the plane with the runway because they are heading there, from such angle you may spot it from 10 miles or even more (at night with good weather), but again, the chance to be in that narrow stripe position when you happen to need it is nearly zero.
By the way listening to such automated broadcasting is way more likely a way, how you learn about the airport existence. And there you learn about the operating regime as well.
And even more likely you find that airport in the map, with the frequency of such automated broadcast and all those details you learn from there...
Since the message was given in context to the storm, i understand this as this airport normally having the lighting on all the time, and now changing to on demand operation due to the storm. That makes only a few days of difference in electricity use
I undersood it as the storm triggered the listening to that broadcast.
However there is one good reason for switching to the pilot activated mode in such case: During a storm, there is very high risk of a commercial power outage. So the lighting has then to rely on the backup battery, which provides just a limited runtime for a load such as the lights.
The mode switching can not happen in an unexpected way - because at that moment there culd be someone just landing on it, so it would be quite nasty surprize for him. So the lights are switched to the pilot activated mode upfront when the storm comes scloser, so from now on the lights will burn only for a short time for an aircraft to land, so the batteries can handle that without any glitch regardless when and if the power will drop.