Yeah, it's kind of situational, but the benefits you get from it are HUGE. It lasts 24 hours, and grants immunity for up to 12 people to poison, disease, fear, and grants adv on WIS saves and extra HP.
I'm playing an 11th level tempest cleric in HotDQ and let's just say before we went to take on a green dragon in its lair, I cast that spell and it made all the difference. What very well could have been a TPK turned out to be a relatively easy encounter. Even the immunity to fear alone makes it completely worthwhile when planning on going up against any dragon. The immunity to poison (against not only the dragon, but the spiders right before the dragon) saved probably over 200 points of poison damage.
I'm playing an 11th level tempest cleric in HotDQ and let's just say before we went to take on a green dragon in its lair, I cast that spell and it made all the difference. What very well could have been a TPK turned out to be a relatively easy encounter. Even the immunity to fear alone makes it completely worthwhile when planning on going up against any dragon. The immunity to poison (against not only the dragon, but the spiders right before the dragon) saved probably over 200 points of poison damage.