I just cannot believe all the people in this thread... 3 pages!
The reason the blank key is there is staring you in the face...
How much would it cost apple to manufacture a whole new set of aluminium plates to make a small volume of keyboards with that one button missing?
The answer to your question, is that this keyboard is a normal stock keyboard with a few of the keys icons changed. What could an ipad do with a control, alt and command button?
The ipad was designed to be cheap, and that means the accessories have to be cheap. Creating a whole new line of keyboards, with new machining molds and new templates just to remove a couple of buttons which may be useful in the future is a dumb dumb thing to do when trying to be cheap.