Is the accuracy configurable? I'm not certain. It makes a fairly precise map of your route. I can certainly always tell which road I traveled down. And often which gas station I stopped at for a snack.

You're probably correct that you could disable most of the data protocols on an iPhone to save battery life. I would like to see battery use tests that compared the cell tower method with GPS, though. Especially in areas with weak or no signal. I guess, because we're talking iPhone, there's no real way around that (except maybe pulling the sim card), so either you have access to cell towers and can use that data, or you don't have access, and you can power down. I just find that full time GPS use seems to draw less power than searching for cell signals in a dead zone. So in a situation where both are available, cell tower data may consume less batteries, but in poor coverage, using GPS only might save battery life if you could get the phone to stop constantly looking for a signal. That's where the iPad works well for me: when I turn off cellular data, I turn off all communication or attempted communication with cell towers. Power lost from GPS usage then remains fairly small. An app that made the same thing possible on the iPhone would be welcome. An app that did the opposite, favouring cell coverage over GPS, could also be nice, but would probably see less use for me since every trip seems to take me out of coverage zones at least for a little while.

What would really be nice is if there was a way to disable the cell chip on the fly, and an app could use cell data when available, but then turn the chip off for 15 to 30 minutes or so when no cell towers are found and switch on the GPS in that situation. But as far as I know, the cellular chip is either active, or the phone is in "airplane mode" which also disables the GPS.