[wongarsu]

It's specifically the ones with three dots in a circle that are only there for the visually impaired. Some vibrate, some have a spinning thing on the bottom.

If they don't have the three dots in the circle they usually do control the lights. Newer models also show a red light on the side of the button when pressed, similar to the UK lights just more subtle. But there are also plenty of old buttons around that don't.