Turbo late reply but at the time it actually was the most cost efficient second item for Seraphine. I always preferred it over Cosmic under most circumstances because of its low cost, decent AP and haste so you can build Rabadon and spike faster. Right now I prefer Cosmic over Seraph's with my so-called "jet thruster" Sera build with Phase Rush :)

thank you very much for the compliment!! if you have any questions I'd be happy to answer :)