I'm of the view that highway=footway should be used for walking paths that have been built and highway=path for just a worn path from usage. In particular if it's signposted as a walking path it gives strength to being higher importance and therefore highway=footway compared with highway=path.

However I realise that other mappers generally use highway=path for any bushwalking track and highway=footway for essentially a non-bushwalking track.

Based on surface=metal and this being part of the major Coastal Walk track, I think highway=footway is better to raise the ranking compared to more minor walking tracks.