Tox grenades should obscure enemy’s vision the same way as smoke grenades do.
Trash variety enemies, who stand in a fire, whatever fire grenades pool or in the fire arc of a flamethrower should think about their self-preservation first, and leave the hazardous area before taking any other action.
Where it comes to fire, I agree.
(with exception for poxwalkers - they should have no self-preservation instinct whatsoever).
As for tox bomber - for the ranged units outside of the cloud? Yes.
For the melee and ranged units inside? Nope! Tox gas works as both buff for enemies and depuff (Ba Dum Tss) for the Kill Team. I like the feeling of panic when congaline of ragers and assorted heretics turns on green torches in their eyes.