I would suggest that this is merely an additional tool being given to jurors, a mechanism by which levels of depravity can be measured.
Prosecutors are taking a cheap shot by bringing in phony science to intimidate jurors from exercising their independent judgment.
No one is suggesting that the jury be taken out of the picture and replaced with this scale. It shouldn't intimidate anybody, rather it may help them to understand the reasons why a truly evil person deserves an exceptional sentence.