system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What does the button on either side of the cross walk actually do?
gpt
It depends on the crosswalk.  For some of them: nothing.  The pedestrian will always get a signal to cross eventually, and the button is there to make them think that they have some control over it so they don't attempt to cross before they get the signal to do so.

For others, the pedestrians never get a signal to cross unless the button is pressed.  This usually happens either when the intersection has traffic signals that change quickly, and don't give pedestrians enough time to cross (so pressing the button slows down the timing of the lights at the intersection and causes the pedestrian crossing signal to light up), or when the traffic that needs to stop for you to cross will never stop unless cars are detected at the red light at the intersection (so without the button, you'd have to wait until a car showed up, which could minutes, or hours).