"2) Since is connects only with WiFi, why only for iOS?"
It's not, it comes with software for Windows and OSX to stream from it too, but the review seems to have missed this altogether. Elgato are primarily a Mac/iOS supplier, so don't hold your breath for any other platform, though.
It is expensive, but saying that a USB dongle would do a better job does slightly miss the point. I travel quite a lot and often find that I can only get a usable signal on my portable DTT stick if the aerials are against the window, but in a lot of hotel rooms there is nowhere to put my laptop that's anywhere near the window. The only solution I have at the moment is to carry long extension leads and run them around the room, which is a massive pain; something like this could potentially be quite useful.
But not at that price, that's silly.