Being evil isn't necessary. They just need goals. "Destroy all vampires" or "eliminate the Church of Asmodeus" would require a whole lot of infrastructure, too.One way to make money relevant is to run an "evil" campaign where the goal of the party is to take over or destroy the world. This would involve things like building a base of operations, recruiting followers and minions, remaining secret etc that would require wealth, and wealth could therefore be a legitimate target for an adventure.