I use it once in a while. I'm far more likely to use it on my Mac myself.

Google will release their own app (with the bonus of ads, most likely). So Street View will be on the iPhone if you really need it.

Because there are few to none, or well hidden addresses. Recognizing a building from street view is sometimes easier than hunting for the hidden address. But, as you say, google will still be available, so no great loss.