This flagship launches later this month and, according to the latest official teaser, features a display with always-on capabilities.
http://www.notebookcheck.net/LG-G5-to-feature-Always-ON-display.159036.0.html
Nokia did it in the past. Remember glance screen.
Sure, it's been around for a while. They just need to get it right and avoid sacrificing too much battery life.