The player waypoint disappers after zone travel. Tested without any addon, of course.
How to reproduce:
1. Being in Stonefalls, open world map, set player waypoint, close world map
2. Interact with wayshrine, zoom out: Still there
3. Zoom in to Deshaan: Still there
4. Travel to Deshann, open world map: Gone
5. Zoom out: Still gone
6. Zoom in to Stonefalls: Restored by ZO_WorldMap with saved, local coords.
But if one could convert local zone coords to global coords and back to local coords of another zone, the waypoint could be restored on any zone map. Not just the map the waypoint was created in.
This leads to
Wish List » Map Scale and Offset.
@ZOS: Thanks for reading this.