Yeah i think its only a Easter Egg, but it would be interesting to see what would happen IF/WHEN the Company go to Planet 4.
I would assume.... that the Covenant is NOT the only Ship who wants to go to Origae-6 with Colonist to START ANEW!
So i assume another Colonist Mission is incoming a Few Years after the Covenant Arrives at Origae-6 the Crew/Colonist would likely have NO idea about what happened to the Covenant or Prometheus..
I then would assume another Ship could be heading after that, ONE that is a Military/Scientific and that is AWARE of what had happened via Davids Advent Message.
I then assume the Engineers with Walter will make up the 3rd and 4th of the Parties who will eventually arrive where David is off too.
As thats what RS had said about the intended Plot for the Sequel to Alien Covenant. (Be 3-4 incoming Parties to where David is going... ONE will be the Engineers who return and Discover what Happened on Planet 4 and would want to Catch the Culprit).