If mutantum magi get mutantum magic as their free option why would they want to use the extra spell mastery options they have?
The only way that question could make any sense is:
How are the Mutantes spell masteries listed in HoH:TL pp99 useful?
- Not all of the Spell Mastery options are identical to the non-Spell Mastery options.
- The Spell Mastery options could be picked up for spells they learned from non-Mutantum sources.
Also note that Mutantum Magi can teach the various masteries to other magi (last full paragraph of pg 97) - the only way non Mutantes can get these abilities aside from taking the required virtues.