Let’s not confuse arena shooters with BR games, just cause they are all the rage right now. Nor battlefield games either for that matter. It is a different type of games and it is nonsensical to even mention their mechanics.
It’s not just Mercy, Zen Discord Orb, Bap Amplification Matrix, Orisa Supercharger, and Ana Nanoboost, are also sources of damage boosting. Why does everyone only thing Mercy does it?
Rez made her an issue thou, allowing dps to take more advance positions at minimal risk.