Significant inflammation reduction, which is another factor in ASCVD. More plaque sticks to you the more inflammation there is. It's a feedback loop, as well. There are some that will even claim inflammation is the real villain in ASCVD, not atherogenic particles. That's not the majority position and ignores a metric ton of research, but what both camps are in agreement on is that more inflammation makes the situation worse.
Another is that they help stabilize plaque - by calcifying it. Which sounds like a bad thing, until you realize some of the greatest risks here come from plaque breaking off, which soft plaque is way more likely to do. Calcified plaque restricts bloodflow, but doesn't throw bits of it off to cause even bigger issues.