According to the insane people here who can't accept that their favorite runners are slower than s-hit, they've apparently designed this defense mechanism that allows the use of conversions/worth numbers for runners.
You know, so Usain Bolt is not the fastest man on earth. The fastest man on earth is actually some Chinese guy whose name I can't spell, who ran an 8.01 because of wind, humidity, altitude, track condition and shoes. Oh, and because he beat a guy who ran a 'worthed' 8.04 seven years ago, and who was running against him in a full body cast because he fell out a seventh-story window.