I mean, as another mercy example, some, very successful mind you, mercy's dmg boost, some pistol (honestly unless you're boosting a soldier or bastion that's hitting things the pistol does more dmg, but that's another story) how do you rank these two? Which does Blizz decide has more value?
Some people play(ed) very aggressive ana, do you hurt the people who don't get as many kills?
What about super agressive zen's vs buff/debuff zens?
A zarya against a team that doesn't shoot shields vs a zarya agains a team who does?