[Keeper of Dol Guldur]

More importantly, one has to note that the Elven Rings did not have the power to destroy, only to create and preserve, and that fire, that Flame of Anor Gandalf wielded, Narya, could only be used in a defensive way to help preserve/defend. Plus, the light of fire is a red oppressive light, as opposed to the clear white shaft of light he blasted at the Nazgul; Tolkien never fell short on the imagery for a reason, to set the mood. If it was fire at work, we'd have seen a fireball.

As for use in helping with fireworks, blowing smoke rings, and lighting torches, why make an Elvish Ring of Fire, when fire's very nature is to destroy things. I think it was made for lesser burning, besides mirroring Gandalf's warmth and kindness, and his hot temper, it helped him heal cold hearts like Theoden's, and I don't doubt it helped his pyrotechnics; on Caradhras Gandalf had to chant words to light the wood in the snowstorm; at the Pelennor he said no such incantations. I would not be surprised if the magic of the rings had to be awakened by incantation; even the One Ring had for it's power to be awakened to have a Ringspell.

It also seems to me that the white light was meant to be associated not just with Gandalf "the White" but with the Phial of Galadriel in some way.