CES, gadgets like this are why I love you. CES, gadgets like this are why I hate you.
The Ion iType keyboard is pretty self-explanatory, which means you already know if you think it's a stupid idea, or a brilliant idea. If you're conflicted, here's a hint: it can be both.
The keyboard is limited to typing in one app, not because of some kind of engineering shortfall, but because that's all that Apple allows - third-party apps or accessories can't serve as text input devices, which is why dictation apps are all self-contained. Basically, you can export to email, save or copy text in apps like that, and that's exactly what you can do with the iType's bundled app. Typing is fine, shift and caps lock keys behave as you'd expect, and although the text input isn't totally instant, it's very close. A battery is built in, which keeps the keyboard running and recharges your phone for a few hours.
It works, and its heart is in the right place, but that was never really the question. So, does it make sense? The iType essentially turns your iPod or iPhone into a netbook. A tiny, gimpy, flat, slow netbook. It'll only be $US70, so if you don't have an iPod Touch, want a tiny-top for sofa browsing and are strapped for cash, then I guess you could buy one. It'd make a good icebreaker, too, as long as you don't mind your new friend's first words being "HAHAHAHAHA, LOOK AT THAT GUY."
You probably have a laptop already, and you should probably just use that. The iType should be available in Q2 of this year.