You may be right about your keyboard comment. I like having my little Sony Google TV controller in easy reach at the moment, but with voice search, I can imagine a day without it.
In my humble opinion, the area where Google TV really kills is in media aggregation. I can enter a few search terms, and suddenly video, audio, and who knows what else is available on my big screen TV. Is it on Netflix? Is it on Youtube? Is it on Amazon? It doesn't matter. I just search in one place and press play. Ultimately, this list will include Hulu, ABC, NBC, Comedy Central, Fox, et al. We will have to wait for the content providers to decide that advertising to web viewers is just as worthwhile as advertising to cable viewers.
Imagine a TV experience where everything is video on demand from thousands of sources, but searchable from one place. You won't even need a cable subscription.