If I understand, "honest" voters in the score-like systems stick to some magically-shared mapping of their own utility to scores on the ballot (totally unreasonable, but let's grant it). Strategic voters, meanwhile, just use the ballots to maximize their own utility.
Let's take the simplest, common scenario of two clear frontrunners. In score voting's one-sided strategic scenarios: - Honest voters who support candidate A will put down magical normally-distributed numbers. Their scores for A end up perhaps 10-50% higher than their scores for B. - Strategic voters who support candidate B will maximize B's chance of winning by putting down the highest score for B and the lowest score for A. Score for B will be uniformly 100% higher than scores for B.
In this scenario it takes perhaps 2-10 honest A voters for every strategic B voter for A to win. Yet somehow, the VSE for 1-sided strategic score scenarios are all much better than plurality, and equal with approval?
This is a commonly-discussed downside for any score voting system, where it gives strategic voters extra power, and, in these 1-sided scenarios, is worse than plurality. The downside is appearing nowhere in this data.