Back in ye olde days, computers worked in the sRGB colour space.. basically the range of colours that everyone (well Microsoft and HP, but everyone followed) used. Having a standard means the red that guy A makes his website is (mostly, close enough for most) the same red you see when you look at it on your computer.
This is fine, except sRGB isn't all the colours. sRGB is the triangle in this bigger space of colours:
Wide gamut (HDR for example) means using a larger colour space, a bigger triangle with more colours. Which is great for content that uses that colour space.. image editing, watching movies, playing games that support it, etc. Everything looks better.
Problem with that becomes when a source that wasn't created with that in mind is displayed in that higher range of colours.. things will look different, not as the creator intended. Everything generally looks more saturated or somewhat off.. reds can look more neon red, etc. Web browsing being one huge one.
Some people don't really notice and don't care. I can't stand it for some reason.
Some monitors have different modes, my old Dell was a wide gamut monitor but it had an sRGB mode so that websites and stuff looked as intended, so I could flip back and forth if I wanted.
But it's a pretty subjective thing, some people couldn't even tell the difference while others would instantly see. Not being able to have an sRGB mode would kill it for me, but it might be perfectly fine for you.
What I don't now is if Windows helps with these kinds of things nowadays.