I'm also questioning the necessity of this display right now. The new 2017 LG C7 costs about the same, supports 1080p @ 120hz AND has fantastic support for HDR. And lag is quite good 25ms for both game and PC mode. Possibly lower at 120hz mode but nobody has tested it from what I have seen. Only downsides are that they are maybe too big for the most people and they do not have a Displayport.
Is this Dell too little too late? Well, I still kinda hope that it does well so that we may see more OLED displays on the market and hopefully even LG eventually gets his head out of his ass and make monitors or smaller TV's based on their RGBW system which has better burn in resistance and better lifetime.
While I do love LG's OLED TV's, 1080p @ 120 Hz isn't very useful as a monitor. Plus, huge space requirements to push a 55" monitor back four feet on your desk.