My understanding is that a cyclepath is a path which is primarily or exclusively used for cycling. The tow path is a shared use path, cycling is permitted on it, although discouraged in narrow spots such as under bridges. As the paths is narrow cyclists need to be aware of other users and slow down when passing them which is not something I would expect on a dedicated cyclepath. In addition to this Strava in my experience (and presumably other similar apps) seems more likely to route you off-road onto a cyclepath than a path with permitted cycling.