I have been trying to find a use for this spell because in spite of the debuff, it's a pretty strong instant heal with 0 or 1 stack that is capable of (as the name implies) saving people from dying in some situations.
In particular it seems to perform well in non-ideal circumstances - such as progression - in fights without constant raid damage. I used it last night while healing H Iron Maidens because my guild was making our first attempts and naturally that involves people screwing up (i.e., taking a lot of spike damage) as well as less than on point healing because we're still learning to deal with the mechanics. It ended up being about a third of my effective healing. More importantly, it definitely contributed to keeping people from dying in some situations. The ability to bomb an instant heal on a target can be pretty useful.
It was much less useful on a fight with constant, raid-wide damage (e.g., Blast Furnance), even on progression - which makes sense.
Anyone else trying to give this spell a shot?