On OLEDs, high levels of ambient light hitting the monitor tends to wash out blacks, making them appear dark gray, thereby subverting one of the most clear-cut advantages of OLED.
So you'd also not see this on other types of displays with a quantum enhancement film (i.e. FALD MiniLED + quantum dots), it's specifically QD-OLED that has this weakness.
This is to the extent that if the self-emissive quantum dot demo from this year's CES was real, even that won't have this issue (although it will likely still do have the stupid triangular subpixel geometry like on QD-OLED, as the demo unit also had that).