http://m.popsci.com/gadgets/article/2011-10/so-um-why-does-new-google-phone-have-barometer-it I was checking the sensors on my phone, when I saw there was a pressure sensor.... wtf? Lol. So does maps use this like that article suggests? Or is it a pointless addition to our phone? Does it use battery? Can it be turned off?
From what I've read, the main reason is indeed for location finding. It makes it a quicker to find your location if it has your pressure data. Don't know how much it affects the speed though. I don't think you can turn it off.