By blinking unobtrusively, the notification LED light discreetly conveys to the user of any potentially important message or call.
[5] Starting 2019 most smartphones vendors have stopped adding the notification LED which could be explained by the advent of AOD and a drive for smaller bezels.
In early smartphones running Windows Mobile or the Android operating system, the LED notification light was also a fairly common feature.
These smartphones usually had LCD screens, so without the LED present, the entire backlight behind the display would need to be turned on to check for any new notifications.
There is also a focus by smartphone designers to minimize the screen bezels or keep them very thin, thus leaving no room for the notification LED light.