Nowadays, the technology is at our fingertips and we have much more insight on how to use to be more efficient. We can put many measures in place so that our engines can be good at more than 1 metric. Why not have everything when you can?
Variable Valve Lift and Variable Valve Timing are processes that enabled us to get better gas mileage and make more power. In addition, they help us be a bit more environmentally conscience without affecting the performance on any level.
As always, Engineering Explained is here to dive into the concept. Check it out!