Matt, it is, if wifi is running. GPS, if it's warm-starting, can take as little as 3 seconds, so wifi is technically faster, but it's going to take you more than 3 seconds to dial and be answered. And GPS more accurate, if they need the location at all - say you dial 911, then pass out. If you're talking to them, about the only thing E911 (phone reporting the location in 911 calls) is used for is to make sure you're not in one part of town but reporting an incident in another part of town. Unless you explain that, it's suspicious. But "a fire on the top floor of 123 Any Street" is the most accurate. You can give details that no phone can. (Of course if you're out in the middle of nowhere, it's great - "I'm about a 90 minute bike ride from the Shell gas station" isn't very accurate.)
But towns have spent money to upgrade to E911, so they have to at least log it to show people that it was worth the money. (I doubt that many emergency dispatchers pay attention to it unless it sounds as if you're not being honest - like they hear a ship foghorn and you're claiming to be miles inland.)