What good is a Paladin's Divine Sense against invisibility?

Question

From the PHB:

The presence of strong evil registers on your senses like a noxious odor, and powerful good rings like heavenly music in your ears. As an action, you can open your awareness to detect such forces. Until the end of your next turn, you know the location of any celestial, fiend, or undead within 60 feet of you that is not behind total cover.

What happens if such an enemy is invisible, though? I know where it is but can't see it, so I still have disadvantage hitting it, right. But if so, what's the advantage of sensing them in the first place? Or does divine sense actually allow my Paladin to hit it like it was visible?

Answer 1

No, Divine Sense won't allow you to hit it as if it was visible. Invisibility says that:

Attack rolls against the creature have disadvantage, and the creature’s attack rolls have advantage.

and Divine Sense does nothing to change that. So what's the advantage of sensing them? Well, the advantage is that you sense them. If you use Divine Sense and discover that you're surrounded by undead and fiends, isn't that better than not knowing?

You could make the argument that if you knew to use Divine Sense, there wouldn't be any point to using it. This isn't really true, though: there's a big difference between knowing that there's something lurking nearby and knowing how many, where, and approximately what creatures are lurking nearby.

Finally, the most important benefit: knowing where it is means that you know where it is. This allows you to use spells like Dispel Magic to remove its invisibility, or just spells like Fireball to hurt it and invisibility be damned. For that matter, you said that you still have disadvantage hitting it, which is true, but at least you can try to hit it. (If you didn't have Divine Sense, you wouldn't even know where it is, you'd just have to swing your sword at a random square and hope. Unless you hit, you won't even know if you guessed right.)

Answer 2

You can attack the invisible creature with disadvantage

PHB page 194 "Unseen Attackers and Targets" says that if you cannot see a target for whatever reason, you get disadvantage on your roll. Divine Sense says nothing about being able to see a creature, only knowledge of its location.

"Unseen Attackers and Targets" elaborates that when attacking an unseen creature, you must guess which square your target is on, and that if you guess incorrectly, you automatically miss. Because you know what square the creature is on, you can attack that square with disadvantage on your roll. You can also inform your allies of the creature's location, allowing them to attack that square with disadvantage as well.