It depends greatly on the game. I've seen a huge difference in games like Control where the game itself was used to feature that... Well... Feature! You can see it in the quality of the lighting and the reflections. You also get better illumination on darker areas thanks to radiated lighting. It's much more natural looking.

dlss is a brand name both amd and intel have their own version of the same thing, and they are only a little worse if at all.