Is it? My girlfriend is probably the only person I'd be comfortable with sharing my location data with, given a reasonable purpose (the one in this post would be good).

This depends a lot on your SO and your relationship to her/him/them. Given exactly the pretext from the blog post: I can easily think of a past relationship where I'd totally agree with you (very distrustful person who could not have resisted the urge to maliciously interpreted the data), and another relationship where I'd be totally cool with it (except I wouldn't want the heat map to be public). For most of my past relationships (and my current, final relationship) however such a request is unrealistic anyway; they simply don't have the technical ability to do such an analysis.

Your girlfriend won't resell it or share it with insurance or government agencies as easily.

A girlfriend may not be as trustworthy, as some people seem to think or at least no more than what is selfishly beneficial and to her advantage. Lots of guys find this out, way too late.