Aside from blocking calls and texts, does it do anything actually useful? I was hoping for a mode with easy to use buttons for driving and/or more voice control.
Not really, it's just to help avoid distractions while driving, and to easily set-up your car's Bluetooth to accept void prompts and stuff. Not much for now, but that doesn't mean it can't be improved upon with future software updates. I personally think it'd be nice if it would launch an app of your choice, like iHeartRadio for streaming tunes while you drive, or your favorite GPS application so you can find directions.
It's in its infancy for now, but I see it becoming more mature with time.