When did Steinberg use to say that ? 15 years ago ?
The old EIST was since replaced with Speed Shift which is much more faster and completely transparent.
And also Cubase is one of these programs that make great use of it, if not the best.
So, really, there is no reason to make the CPU run at full speed 100% of the time, we are no longer in the early 2000’s…
Such a thing is no longer a problem with 14 nm and lower CPUs. The number of transistors and working frequency is so much higher compared to CPUs from 10-15 years ago, that dynamic clock no longer causes performance issues with audio production, really.