Because Ash's basic weapon explodes after a fixed distance, with good spacing she can easily hit Vivian around her Deflector Shield, even damaging both simultaneously. Similarly, the exploding shot means you can easily damage Vivian's ultimate drones

Sha Lin's ultimate can make him hard to track, but throwing down a Sensor Drone near where he was last seen will reveal him for your team and partially negate his ult.

Vivian has some of the highest sustained DPS in the game, especially with her ult active. If an ally gets hit by Yag's ult, you'll easily be able to shred through her ultimate health to save them.

In a straight DPS fight, Vivian does more damage than Zhin. If you have Deflector Shield up, you're likely to win the 1v1. Be wary of his ultimate and Whirl, as both will ignore your shield and the latter can place him behind you.