Useless honestly.
Her Sacred Flame was already useless enough due to its terrible 50%-60% accuracy, so giving her a Fire Bolt that is even lower (30%-40%) and uses a completely different main stat is even worse so I removed it from the ability bar in an instant. I just give her a Crossbow and go Dexterity with her. Much more useful that way.
I typically don’t use it for direct attacks, I use it for environment attacks. And with my builds, I tend to have to resort to yeeting candles lol. But yeah I agree it’s best to let us change them out at first level up.