Plenty of electronic devices (even those inexpensive from the Far East) have some kind of LEDs to indicate the state of the device. A good example may be a stand-by LED on the on-off switch of many TVs, another would be power-on LED on many laptop power supplies. Depends on a type of information, different color of LEDs are used.
Usually green color says that the device is in good state and don't need attention, it's the default color for power-on indicators. Yellow is used to indicate that there are some information or some events that the user may want to check, but they are not critical. Red color shows that something was wrong, that user should pay attention to the current state and maybe made some actions.
This is also a question of a good user interface, especially now, when everything tends to use white or blue LEDs - they are something fresh, something that wasn't available a decade ago. Yes, maybe they are cool, but they are also non-intuitive. That's a different story.
It may sound strange, but the selection of greed-yellow-red colors is not an accident, but is based on thousand of years of our human history. Green is intuitively connected with leafs, forest, bushes, trees - places to hide, that are much more secure than an open space. In open space, it's much easier to be observed by predators. Red is the color of fire - danger that kills and destroys, especially before human kind learned how to handle it. A lot of poisonous plants have red fruits too. Yellow is often a skin color of toxic animals that says "don't eat me, I'm toxic, you will die - I warned you". It's a color of information.
Even devices that cost tens of thousands of dollars have those LEDs that have a color selected just because thousands of years ago our ancestors were living like today monkeys and we still keep those references! That's amazing!
I think that if some day advanced alien race would get one of our electronic devices and reverse engineering it, they could understand what it is, why we use it and how it works. One thing that they wouldn't be able to understand would be why we choose those colors. That would be only possible if they would analyse our natural environment and our history.
It won't end, a lot of software applications also use those colors or have some widgets that simulate LEDs. In addition, sometimes there are also GUI widgets that simulates knobs, switches and other mechanical elements - maybe we live in an era that adds another level of this inheritance? What about floppy disc icon used as "Save as"? Who have a floppy disc, yet we still have this icon in many applications.
BTW, it's also interesting that e.g. traditional caliper works only because our eye and mind has great ability to misalignment among two line segments, however, we suck in different areas of image recognition (e.g. checking perpendicularity). An alien could analyze a caliper, but without knowledge of the biology of a human eye and human brain activity, it could be only possible to make assumptions why we are using calipers and not some other ways to measure distances.