It does say in the feat description that the bonus to hit from the feat cannot exceed the character's BAB, but there's no cap on the damage. I think it's mainly for multi-class spellcasters. It's in the sidebar titled feats for hunters(rangers) so I guess it's tentatively meant for ranger/wizards. It would be particularly useful for fighter/wizards, eldritch knights, bladesingers, asassains, and even bards.