Yeah, I definitely don't disagree you can purchase chargers cheaper elsewhere. The thing is though, I'm pretty forgetful about that sort of thing. So I always end up forgetting to recharge it once it's used up so when I would head out to Disney I wouldn't have anything to help when my phone went low. Or if I do remember to take them out to charge, then I forget to repack them when I leave the house. With the fuel rods, I can just keep it in my park bag and know, if it's empty I can just get a new one immediately, without having to worry about it!
So, I guess I'm willing to spend the extra money to have that convenience factor!