Well, it's a pretty far-fetched idea anyways, but, a few things to consider:

- I never said you have to use wifi. You're right that radio would have a much greater range. - The main advantage I can think of for a system like this would be speed of deployment. In an area with poor line of sight, they could be used to bridge the gap until a proper base-station can be positioned. - They're more versatile. For example, they could be used as a mobile PA system. - Of course, it's all hypothetical. Nevertheless, it'd be fun to implement and more useful than the Pirate Bay's idea of a flying datacenter.