Accelerators are worthless to measure distances even if they were super precise. This is because you have to do double integration to get distance and the errors only accumulates.

I never said that a distance scale was obtained by applying double integration to the accelerometer output. I only said that in order to measure absolute distances, as opposed to relative distances, it is necessary to have an accelerometer, since no other data provides an absolute scale. See the other reply by one of the founders for the details.