As the path doesn't seem to exist "on the ground", isn't readily visible in satellite/aerial imagery, isn't a designated PROW, and isn't particularly hot on Strava heatmap (https://www.strava.com/heatmap#15.17/-3.21240/54.58009/bluered/run - aside from the lower section) it maybe doesn't belong in OSM and could be deleted. As you say, we don't map just to appease any particular router or renderer, so I'll leave the note open for a bit to give other local mappers a chance to comment before making any changes.