Basically yes. If you want to get technical about it, it's not tracking movement it's tracking acceleration, which you can then integrate twice to update position.
Are there any records of how currently available consumer devices measure up in this regard?
https://github.com/nisargnp/DeadReckoning
I read a paper some time ago which suggested that mobile devices are still nowhere near good enough to use this e.g. for navigation around a shopping mall.