LED lighting wouldn't exist if not for blue LEDs. And neither would much of modern display technology. The importance of this discovery was not because we could make shiny blue light with it.
The vast majority of monitors and televisions are still LCD, and they would work Just Fine if they were still using fluorescent backlights.
It would have more of an impact on phones, but not earth-shaking.
Do blue OLEDs even use the same technology?