Well, the idea is cool, but as a gunner I'd hate everyone who used them against me.
Still, if we could act normally, but not see, it'd be awesome addition in my humble opinion. I'd make aiming it properly a hard biscuit, though. You'd need to land it nicely to have any effect, otherwise it'd just be fancy fireworks.
Or it'd be a quality of Lochnagar flares, where the sheer strength of it would work as a flashbang.
Btw, didn't we have this suggestion somewhere already?