I've been reading about Wizard's Communion & Mercurian Magic.
This quote from ArM5, pg 46 in the Mercurian Magic description has gotten me wondering about further things.
When casting a spell using Wizard’s Communion, you may add your Mastery score (page 86) in the spell being cast and your Mastery score in Wizard’s Communion to the effective level of the Wizard’s Communion.
To me this begs the question of what benefits other than this that someone should/would get out of investing in a strong Spell Mastery of Wizard's Communion? Is there a point to doing this?