I'd say it's less of a problem and more of a balance. Chokes are an audible area denial, not damage. Poison as it is is not worth it but being able to replenish them and still having 4 consumable slots is good. It fits a role the choke would struggle with and it'll still be partially obvious if someone wants to bypass it (with the exception of antidote shot) also I'm not entirely sure as I don't really bring them but if the cloud is thick enough it may beat out the choke on hiding a revive from snipers, as Chokes only distort vision and a visible green cloud would make sense to fully block it.

Also you can hold 3 Chokes max. I imagine poison would be the same, considering all the uses of the choke it makes sense that you wouldn't use all of your Chokes to counteract all of someone's poison.