They are pretty cool and neat looking, but leave them out of Ultimate lobbies. They don't contribute at all and there is always space to join someone else's party beacon for the triboost.
Enemies in the Ultimate fields are pretty spongey and hit hard. Due to the lower gear levels, moons get burned through really fast, so having 3 extra players both helps kill faster (for your loot gains) and provides more people to revive you.
Now I patiently await someone telling me not to tell others how to play.