Clearly, it works best when switching to another target won't work. Maybe they lack ranged weapons and don't want to get backstabbed. Or they were trying to force concentration saves. Or the person with sanctuary blocks a hallway or cliff edge or somesuch.
Not long ago my group was charged with guarding a bridge -- which a whole army of orcs wanted to cross. We cast sanctuary on the fighter who just stood in the middle of the bridge, with a cleric behind him for heals. With their low wisdom they got very few attacks in; he lasted quite a while.
Not long ago my group was charged with guarding a bridge -- which a whole army of orcs wanted to cross. We cast sanctuary on the fighter who just stood in the middle of the bridge, with a cleric behind him for heals. With their low wisdom they got very few attacks in; he lasted quite a while.