Each of the performance-enhancing suggestions we've explored thus far have been primarily centered on reducing system requirements and avoiding frame rate issues. But at its most fundamental level, seeking peak performance means improving the user experience. This is because every frame rate hiccup, every crash, and every system requirement that is too costly for a given market ultimately detracts from the quality of the product, and leaves us wondering whether we should have tried harder to tweak settings and fix more bugs before release.
There are certainly opportunities to manipulate Physics Engine behavior that improve all of the aforementioned issues, but Physics Engines also fall into a unique category of having a direct impact on gameplay quality. If important gameplay collision events get missed (such as the player falling through the floor), or the game freezes while it calculates a complex situation, then these have a significant impact on gameplay quality...