This “30%” floating around is a massive misconception. It’s not a 30% increase to her damage at any location. It’s not a 30% reduction in her spread. It’s merely a 30% increase to the distance at which her damage begins to decrease.
To put it very simply… PTR Tracer at 13m still does less damage than live Tracer at 10m against an average-sized squishy hitbox. This is due to bullet spread, which will always be a far more significant issue for Tracer than falloff. Falloff may now start at 13m, but spread still starts at 0m.
The Tracer buff is only effective against large hitboxes and only relevant if Tracer chooses to shoot from further away than she normally would.