Yes. Spirit Dart gives tanks and healers the same damage boost, but tanks already deal several thousand more DPS than healers do. On top of that, it's yet another showcase for how combat works, and especially how skewed FF14 makes it: damage is always useful. Healing and mitigation happen infrequently, and when they need to. This is just how it works, and it's not a paradigm unique to this game. But since HeALeRs sHOuLd HeAL oNLy according to the job designers, they have crap tools for dealing damage. So the way it ends up is, you have a healer given an ability they can use occasionally that bumps their damage up, and a DPS given an ability they can occasionally use to bump their healing up. Weird, the ability that falls in line with how the combat system actually works (i.e., you heal once a minute or so but deal damage constantly) is more useful.