Mostly recursive routing is just lazy or mis-understood configuration. Sometimes it can be helpfull though. e.g. If you have more than 1 router handling incomming ISDN you can redistribute the PPP host specific peer address into a routing protocol then have statics pointing not at a dialer but at the PPP peer address. Which ever box the backup call hits will add a PPP peer address into its route table, pump that into your routing protocol and the traffic following your static route automatically recurses to the right next hop.
Its just anothe tool in the box which is normally, in my experience, used un-necessarily.
