In his old year cabaret show, Peter Pannekoek stated the buttons near crossings don’t actually do anything, they’re just there to just pacify people. I’m fairly certain they in fact do work, though for cyclists they’re mostly redundant: the magnetic loops in the road surface detect cyclists. Only for lightweight carbon bikes a manual button is still useful.
Am I correct in my assumption?
In the Netherlands the buttons seem to do something - at some places, when traffic is calm, the lights are red for all, and pressing the button turns the bike light green. I’ve also noticed a waiting timer for bikes at some intersections that only activates when the button is pressed so I think it works?