OLEDs come with HDR too.
HDR has a clear advantage over SDR. Its 10-bit depth (or more) means (at least) 1.07 billion colors, compared to 16.7 million colors with the usual 8-bit depth of SDR. And the dynamic range difference is 6 stops for SDR and at least 13 stops for HDR.
This means, simplified, that e.g. during a scene with the sun rising, HDR can provide a way more realistic depiction of all the various shades coming with it, while SDR may provide only a "sunray blur", which upon closer inspection especially in 4K may have visible rough edges. And when this gets pushed up to 8K and ultra-wide or large, then it will be even more visible where SDR falls short.
There are several factors for HDR to work properly though. On one hand, there is the actual content, such as a video game. And if the content creator just moved some slider to be able to claim it supports HDR, then that isn't necessarily a great implementation thereof when the final image is pretty much just overexposed, and similarly. And i.e. HDR10 isn't as good as HDR10+.
And on the other hand, it is about the panels at hand. E.g. OLEDs come in at below 1,000 nits, which is not that great to make full use of HDR. Then again, as said, OLEDs can support HDR and can do that quite well actually, but they don't that well for more than short bursts, at least as far as TVs were concerned, with OLED screens for gaming being quite new. And then there is also the issue of how long until it has a burn-in. And Mini LEDs sure can be too bright, especially when used in a dark room, and perhaps not calibrated at that.
But aside from the topic of which type of panel may be the best for what, and at what cost, I don't think everyone will drop HDR to go back to "SDR only".
EDIT: Oh, and watching a video saying "HDR" doesn't necessarily mean one can see it all well on a non-HDR screen, in particular due to the issue of how many colors there are in the video and how many colors a viewer's screen actually has.
And in particular the recording of HDR gameplay can have some caveats in itself apparently. I.e. checking how well Metro Exodus: PC Enhanced Edition runs with a RX 6700 XT OC, recording software said it supports HDR recording, and I set the parameters for it, but the recording didn't look good, (perhaps as the software tried to convert it to SDR for general use as e.g. Twitch doesn't support HDR etc., or perhaps because it works suboptimal at below 4K, or something). And I suppose I could look into how to make it work better (with different software), but that would take me back to the previous point, of that not everyone may have a screen with as many colors anyhow. So recording without HDR now, and long story short, just meant to say that the gameplay itself doesn't look worse with HDR on, and I would likely see more of a boost from it with a HDR10+ screen.