Ok, let’s look at how Mercy contributes.
- Picks? Not really, others do the damage for her…
- Utility? Damage boost, but still relies on others to use it for her… Rez, but it has a 30s cooldown between attempts and you have no agency over where others die
- Heal? Not an amount to write home about… if you’re going to healbot, you might as well play Kiri who at least gets a powerful ult in return and brings Suzu to the table
- Ult? Probably the worst ult in the class… Also Juno’s ult exists and is Valk but 20x better, while she gets to use the heal+dmg boost herself
That sure helps when your tank is getting spammed with nade or lasered by Bap/Zen
Damage boost relies on teammates to hit their shots, you cannot make use of it yourself like Zen can.
Rez relies on teammates to die in a favourable spot and situation.
GA relies on teammates to be positioned well, although it’s a lot more forgiving with the amount of freedom the ability gives.
Other supports can be proactive and function independently. Mercy cannot.
I’m not even saying this to be rude, I promise I don’t care outside of illustrating my point, but Mercy IS carried by the very nature of her kit.
Note the amount of Mercy one-tricks that cannot play any other character to save their life, lest they lose 3 ranks
I cannot remember the last, or even first time someone has ever said “can we get a Mercy, she would be perfect for this comp”.