Like all ITVdigital products, the CI slot is not activated as yet, and may not be for some time
Additionally the IDTVs have a limited lifespan as far as uupgrades over the air are concerned so by the time ITV digital decides to change the encryption system to something more robust, you could find your TV wont accept the new CAM.
The issue of handing the box back when twelve months is up is different for intergrated TV systems, many manufacturers find this is a good way of getting rid of two obselete systems in one go.
But then if the picture is good, then what the heck.