There's games that use it but its impact is debatable. Apparently its Vega architecture that Cerny-san thought important enough to incorporate in the PS4 Pro, but Microsoft didn't deem important enough to include in X1X.
It's a thing and it has uses, but I'm not sure it's the secret sauce some claim it to be.
It does make a difference in some games. Mantis Burn Racing devs talked about how it was an important part of getting that game to native 4k on the Pro. However, that was a relatively simple game. It does have some good efficiency gains in some uses but it's not always applicable. Different games, different engines, and different visual goals will all change how relevant it is. I agree it's nothing that could be considered a secret sauce but it's a nice efficiency customization to include.
I think the bigger impact of it being included in the Pro's GPU will be more documentation and experience with it before next gen rolls around and it becomes a more commonly used feature.