The chances are if you're looking them up on eBay, you're already sold on the why, but just in case you need some more info:

1. Economical and effective way of disguising unsightly radiators, changing them into focalpoints for display.
2. Your heat output is made more effective by convecting the heat into the room, whilst at the same time reducing the heat loss through your windows.  (You can of course improve this even further by placing aluminium foil onto the wall behind the radiator!)
3. HEALTH & SAFETY: Provide an important barrier between the hot surface and a child or elderly person!  Make sure your cabinet also have a smooth rounded finish, this is better that the sharp angular edges of a radiator.
4. Carrick Cooperage's covers are made from 18mm thick MDF and usually from one sheet (dependant on the size of your cover) - this increases the cover's strength and rigidity.
   

WHY MDF?

• Value for money - oak veneered MDF costs a fraction of the cost of solid oak:
• Stability - as there is low water content in MDF it won't warp when used in hot areas;
• Isotropic (no grain) - so no tendency to split.
• Flexibity - MDF paints beautifully, but if you choose veneered MDF, then you have the stability of MDF, with the beauty of the natural wood.