>>282287428
I wouldn't say it's useless in the war to be king. It's INCREDIBLY good support like Tio's healing, just not useful for the caster. It puts her in a kingmaker position, which doesn't really make much sense anyway. Unless her low level spells are actually useful and the team was too unskilled to figure out how to use them correctly.
To be fair, she says in this chapter that she only learned about this spell after the demon king battle was over, so I guess it was never going to be available to her? Which seems like a contradiction because more often than not, you had to cast a spell in ZB1 to figure out what it does, and even then it wasn't always obvious.
I don't think this spell takes much skill to use. It defaults to just copying whatever the original is doing. Kiyo can certainly get extra mileage and use it better than anyone else with a few possible exceptions, but it isn't hard to think up strategies like "Tio shields while the clone heals everyone" or "double AoE gravity attack". You don't even need to think about spells for a copy of Bari to be a threat.