

Inspire allies to perform better or push their limits, bolster them against mental damage and heal mental damage they’ve sustained, raise the morale of a group (especially if that group shares my religion). Bonuses to public speaking, negotiation, religious knowledge, etc.
If I belong to a more fire-and-brimstone type religion, perhaps I can intimidate sinners, make my allies more effective against heretics, etc.
OP already accounted for social situations where you would expect to meet people, though, and his parents seem to think that he should be approaching people in other situations—like in a store, or on the street. I’d be very cautious about that.