We really, really, really need to be able to ping enemies.
Granted, it could get out of control. It will need throttling. Otherwise you’ll be having a big team fight with somebody pinging “Reinhardt here! Reinhardt here! Reinhardt here!” while he swings his hammer in the middle of the group.
But a quick-easy way to signal rando teams “need help with this Sombra” or “Roadhog low health, help finish him off” would be so nice. Yeah, voice comms will always be better, but that won’t happen in every game. Lots of folks not comfortable with voice comms (or not taking this casual game quite seriously enough for them) are likely to embrace enemy ping.