This was not always the case. The iOS app, at least, used to import location accuracy from photos added, but no longer does so. This was reported as a bug. I no longer use the app for this reason. I upload photos via the web interface to preserve the location accuracy.
I don’t think that is the case. I believe the app does use the location of the photo, just without the location accuracy (at least, that’s how it worked when I last used it some months ago).