This is the same where I live. The crossing buttons do nothing during the day (walk symbols still come on for the same length of time), but at night they need to be used. I don't push it during the day, but of course most people still do :-)
I always push the button at pedestrian crossings, even though I'm aware it often does nothing.
Is that because it "creates a sense of togetherness with strangers which might otherwise be absent"? Is it because "doing something is better than doing nothing"? Is it because my "attention is on the activity at hand"?
No, it's because at some crossings, at some times, it has an effect; and life's too short to construct a mental record of the reverse-engineered temporal programming of traffic lights.
I also believe that the hardware is there so that the software can be changed.
I've seen plenty of people follow your strategy incorrectly, perhaps following an operational change that they haven't noticed. They are really just waiting for someone else to come and push the button.
I walk to and from work every day, same route, same crossings, during daylight hours, the same sequence of traffic and crossing, to the degree where one watches the traffic lights and crosses as you see them change, rather than waiting for the pedestrian light.
Anyway, long story short, walked there one evening shortly after getting into this routine, and got halfway across the road before realising that the flow was evidently different at night, and required a button-push for the pedestrian interval.
If they just put up a sign that said "button needs pushing only between hours of X and Y" it'd probably help road safety and save frustration - although that goes contrary to the article. shrug