Seeing as in two out of three fights of our level that I played her she has fared worse than the other PCs survival-wise, I don't think being invincible is an issue. First of all, a great deal of people other than wizards can pierce veils with supernatural senses that aren't the Sight. Secondly, if wizards see a blast of power coming from a zone but not where exactly in said zone, they simply blast the entire zone. Third, there are a great deal of conflicts other than physical. Social and Mental come to mind - as does information/investigation/research, as well as having a goal other that protecting oneself. Fourth, there are always ambushes.
Basically, currently in the game we have
1) A social goddess (spirit, actually) that also attacks at range at +7, weapon 4.
2) A master thief/assassin with true seemings that can veil the entire group as a supplemental at +7 strength for free, so we can ambush the enemy, veil again, then ambush the next round. Rinse and repeat. Plus he has very good mundane stealth, perception and guns skills.
3) A melee guy that easily attacks at weapon 8 and has a physical stress track of 12 boxes plus armor 3.
4) Elena, the resident artillery and ritualist.