Reducing temps and power draw while maintaining performance is useful. Doing it with a performance gain as well? Seems odd to label that "gimmicky".
It's gimmicky because the efficiency gains are not good enough. A 19W decrease, while great, is pretty much nothing when we're talking about a 112W average power consumption. Good and even average CPU coolers and motherboards today, can handle well over 112W, especially with Intel chips consuming as much as 240W or even more.
The temps are similar, 80-85C is perfectly safe for Ryzen, and is still 5C below the maximum rated spec of 90C. Granted the temperature difference is definitely nice to get more wiggle room since a 5C delta isn't all that great. But, temps like this have been found to be normal on the 5800X3D in general, due to the heat transfer issues generated by the 3D Vcache.
Another is that MSI says this is a CPU performance enhancer specifically, but 2.4%is laughable.