It's not that great. It's probably used in the caves because, like others said it has a prayer bonus. Being the only ring with a prayer bonus, it's somewhat valuable because in the fight caves you need all the help with prayer you can get. It's not going to make the fight caves much easier, it's just a +1 bonus. If you're not good at firecaping, it certainly will not make you any better. Just makes the waves take up less of your prayer pots.