Boss as hell for Summoning Magic, It looks like SE intended this to be a staff macro'd in when executing Bloodpacts.
But remember, the Magian Trial Staves give More Attack, More Magic Attack as well when they're complete.
This however, Offers the most SMN magic skill outside of a Staff from ANNMs (which goes up to +10), and Blood Boon+5, Which is a good Chunk of Conserve MP on Bloodpacts.
At the very least, Its magnificent for Executing Bloodpact: Wards, and :rage If you don't want to work on magian Staves :O!