Uploading waypoints and editing with Potlatch is quite involved. The upload tracks facility is really aimed at GPS traces.

I would suggest using either JOSM or Merkaator, OSM off-line editors, which can read your waypoints and track directly. The effort required to learn adding a POI in JOSM is probably less than that required to fiddle with uploading a waypoint only trace.

Alternatively always record a trace when waypointing POIs: having a trace is useful for other things, like geotagging photos.