Ayana's tether stops movement, it's a CC ability that can potentially do damage, a LOT of damage, and has no CD (cooldown). You can pull Alicia out of the air, drag Hans to the ground, save an ally from getting grappled, set up an enemey player or elite to be grappled, with no defense, by an ally.
Also, offline mode with no rewards already exist. Everyone else is asking for the opposite, for the already existing offline mode to actually have rewards.