Looking at that chart just emphasizes how huge of a break KC got. They are guaranteed #1 or #2 with #1 most likely. They could have been #3 if bills, bengals, chiefs all finished at 13-4 (i think)
What's more important a week of no football or potential #2 home game- if you forfeit you get a week off to rest body and soul when both are probably not ready to play this sunday. Even if you play and rest "starters" you can't rest everyone. Also there is no gurantee they win... if they lose they are not any better off in getting #2.
They also still have to go to KC regardless.