In general, it's very rare for support classes like priests to be able to contribute significant damage to enemies, especially considering that the elemental attribute of the recent goblin boss wasn't known - clearly not dark or light element.
Light or holy elemental attacks are highly ineffective against all other elements except dark. As a result, support classes without active offensive skills would struggle to farm experience for leveling up.
While support classes are crucial in practical applications, building one from scratch is a dedication that's not easy. They can only become useful in specific situations that rarely occur in a general context.
"But that skill Magnus-something seemed quite effective when used against Morgar," one inquired.