button_operated=yes can be used for all kind of button operated things, as described, for example elevator. https://wiki.openstreetmap.org/wiki/Key:button_operated
In combination with ! a key:crossing 2.4 Traffic signals describes traffic_signals
In text the most common use is mentioned
Which traffic_signals are there? also, sound, vibration.
yes, says, that all kinds of traffic_signals are button_operated, this include also sound and vibration.
Only the green light should/could be, traffic_signals:traffic_lights:button_operated=yes. (traffic_lights ?)
As may things which are developed in OSM , written with the big group of use in mind.
The little groups must be fit in later.
button_operated=traffic_lights, short tag, could mean only lights is operated wit a button.
button_operated=sounds
But when you have both, the : method is better to use.
Under construction:
I am working on a JOSM style to control de tags, now you have to select the node/way, then see the list, read all and understand it.
A symbol, (why, we need maps) In a eye blink you can understand, what is ment. The legend is important, zoom in and see on a level we do not normally draw, what the symbol mean.
flashing_lights=yes/no/always/button/sensor needs the upper right corner.
“else” means, that there is a value, or a wrong written value, what is there, get own symbol in the style.
Here the level, the symbol image jumps to a symbol image with text legend.
And all depends how it is drawn in. To see it, you must visualise it. Otherwise you can not control it.
Image, 25 cm aerial image (pixel have more deviation) and on this spot official measured in Government data, which we can use for OSM, to draw the lines on it’s place.
The zebra is only that part where the zebra is (white) and the crossing:island=yes/no (yes red) is on the spot where you can stand still.
When you think further, there is even the possibility to use :conditional with yes @ (times) at a button_operated.
Need that all to be visualised.
There are a lot of combinations!
Running out of time 
I understand that this doesn’t really work with apps that come with a built-in set of tasks, though.
