Yeah, of course this could be of use, I find the effect exceptional, really does look like you are saying you wanted it to look like. Though I think if you were to add some minor particles to it, such as small bubbles or something, it could look even better. There is usually some random small dirt or things in a poisonous gas cloud. If you get what my point. I think it would also appeal the moderators even more.
Effects do look a lot better with some variety, even though if it is only a gas cloud.