Esuna Confusion

[Imakles]

Did a quick search and I didn't see anything about it, so with any luck some of the more experienced healers out there can help. Esuna's description says it removes detrimental effects, but it doesn't seem to remove any and all negative effects on party members. To me, "detrimental effects" are any nasty effects on party members we can see in the party window; however, that doesn't seem to be the way it's intended...perhaps I'm just misinterpreting it...

My question...what will it remove and what does it not work on? "Detrimental effects" seems like a vague term so I was hoping someone could spell it out in not so uncertain terms.