EB and SF target different defenses. There will be situations where you encounter monsters with higher dex saves and EB against them would have a higher chance to hit.
I would pick none of them. It is very wasteful when there are so many other premium options available. If you want AOE, I recommend picking Synaptic Static. Synaptic Static is already on the Bard's spell list, does psychic damage(good damage type) and targets intelligence(weak saving throw for...
You misunderstood what I said. I didn't say being a Barbarian was the problem. The problem is he made his barbarian worse by mixing in 3 levels of Warlock.