They give people a powerful and vicarious life. They let them do what they’ve always wanted to do, but were too afraid to try. And they create an interactive experience that doesn’t try to persuade them of anything, but rather, creates a playroom that rewards and validates users.
On the business side of things, if a game can build a critical mass of users around it, then it can be leveraged to do something else.
By helping the customer take their eye off the ball and play with something that’s unrelated, yet choreographed intelligently, you create a reason to believe. By encouraging users to actually do stuff, you imprint them with an idea more successfully.
Why show an advertisement about your cause when you could could create a simulation that allows people to tackle it directly?