I believed optimizations like that at a global scale will not have any impact.
Lets say that this nanosecond will be saved trillions of time a day. Resulting in minutes to an hour a day saved globally.
* Not a single user will notice. * In 99.99% of cases the CPU will not be fully pegged and thus that one nanosecond of compute will not be used to do something else at all. * CPU throttling isn't that fast so, you won't even save that much power.
If we bump it up by 6 orders of magnitude to a millisecond that all remains true. Even though you are potentially saving 100s of years of computing time a day. Extremely small gains distributed across very large number of machines don't tend to be as impactful as you would hope on a global scale.
This is not to say that small gains are worthless. Many small gains added together can be substantial.