Something else to consider: When using Fey Union/Aetherpact, the fairy ceases to cast embrace. This means that the amount of healing you actually gain from using it is even lower than the already-pathetic 288. It's effectively something like 180. As you mentioned, Fey Blessing only costs 10/100 gauge and has a 60s CD, so it's basically free. The entire fairy gauge only serves two purposes: adding fake depth to the class, and making you even more useless after a rez.