<em>What is the benefit of this API compared to whats already available?</em>
Where up until now, the first answer to 'You want GPS location?' would have been 'You'll need a native app.', it's now possible to just built a webapp instead.
At least for requests that came our way for building native apps for the iPhone, the most requested feature was 'ZOMG, make it localizable!', where the rest would be just pulling data from a server.
Now, my option is to just built a mobile webapp that can use the lat/lng without much fuss (still needs to degrade gracefully in case of older phones/browsers of course).
I think this also includes support for the Geolocation API found in Firefox 3.5, so they can probably add that to the list, as well.
Edit: Typo
You will be redirected to Google Maps if you click the folowing link:
(You must click "share location" when prompted by the browser, you know, privacy concerns)
javascript:navigator.geolocation.getCurrentPosition(function(position){window.location.href="http://maps.google.com/?ll="+position.coords.latitude+","+position.coords.longitude;});
Drop it in your bookmarks toolbar and presto!Or get it from here http://mylittlehacks.appspot.com/geolocation
edit: looks like you fixed it :D