It seems like Tri-Disaster would be good for binding enemies close together for a bane or to keep them under shadow flare, but it just doesn't work out that way. Cast time is too long and bind is too easily broken. I use it occasionally, once I've bane'd, SF'd, Miasma II, etc and have nothing else to do (usually mobs are almost dead by that point, so I don't see the harm in throwing out a few Tri-Disasters). If I was smart I would just use blizzard 2 as it has faster cast time, costs less mana, and does more damage - however ideally I think you'd want to mix it up, like on Brayflox there are a lot of AoE to avoid if you are close range, something like turn 4 the spiders don't have any AoE so close range is safe. Pick and choose, I suppose.