Not really stepping on Fire Bolt toes. FB can be used as CC as well, and this is already reason enough to use it in most situations. Use of this card is much more limited. If it does less damage to player than Fire Bolt, why to use it? Because eventually it can be used at yourself? It remembers me when upped purify used to cost 1 generic quanta. The effect wasnt (and still is not) enough to put it in deck, because except vs poison decks, would be a dead card. If the damage of this is not enough (compared to other spells or creatures), would anyone care about the chance of get cured vs poison decks only?
About use in yourself, I also think some more damage is good when you can remove, lets say, 20 poison counters. Would you use the card at 5 damage but not at 7 damage? In fact, maybe 10 damage could be ok.