Having recently purchased a laptop with a 90hz OLED display, I can easily say it's one of the biggest "next gen upgrades" I've ever seen. I was watching 4K HDR videos of Gran Turismo 7 on my laptop and then on my 55inch 4K LED TV and the difference in colours and the deepness of blacks is just night and day.
Once you see it you really cannot unsee it. Now here I am on my main desktop with two "shit" 175hz 1080p monitors. The blacks just don't look the same.
Plus, as someone else said, the benefit is that all the slightly older OLED TVs should come down in price.