First of all, lets talk about economic benefits. Games with high economic value can be favored by more organizers. Besides, influential football is the number one sport in the world. Countries all over the world, regardless of their economic size, have people participating in football. In sports, the popularity of Messi is higher than that of the president of Brazil.
There is also another side of that "economic" coin. Having World Cup held in your country is prestige, but it also are huge expenses. Imagine you make hundred of million investment in stadiums, infrastructure, build additional places to live. And in 2-3 weeks no one needs that anymore, if football is not Nr1 activity in your country. All what was built becomes abandoned and start to collapse slowly. I think that all those investment in Football cups or Olympics infrastructure does not pay off at all.