Not all IED's are placed out by insurgents, and not all of the insurgents are rocket scientists, and explosives and the rest of the equipment are fairly expensive if you earn $1/day. Many of the IED's that goes off over here are non-lethal due to poor manufacturing, not enough explosive, in combination with better protected ISAF/OEF/OIF vehicles. So more armor (in combination with ECM, like on the chally in the pic) is absolutly one of many ways to go for better protection for the soldiers.