Linguistic. I am not a native speaker, (though I have a degree in English translation, ha:-D), so I might be wrong, but path sounds too much like a trail, especially in American English:
American English definition:
a way or track made by or for people walking on the ground, or a line along which something moves:
Pathway is in my undersanding more abstract so it can accomodate a wider selection of tags. It sounds weird to have scramble, pathless but also cycleway or shared_use under path but sounds more natural to have it underpathway. Though I just made a cursory search and there seems to be great confusion about the distinction; it might be regionally varied.
I would be interested in native speakers’ perspectives (from different parts of the world). However, I could live with path (though I am strongly for eventually deprecating highway=path and promoting either path= or pathway to primary tag).