Constellars are decent if you use that trap to return monsters that battle them to the hand. Swarm the field, let your opponent attack, then shuffle their monsters back into the deck and counter attack next turn
The problem with your statement is that, not only do you have to hope that you draw the trap card in question, but it also has to be allowed to activate during a key moment. What good will that trap do if your opponent blasts your back row during the Main Phase, other than make your opponent wait until next turn to attack? And what if the traps are all at the bottom of your deck?
Furthermore, there are plenty of other traps that can work for other decks, without relying on sub-par monsters in order to function. If your opponent kills your monsters via card effects, that trap's not going to do too much. Don't get me wrong. Constellar Meteor can add a surprise aspect to the deck, but without it, your strongest monster has 2400 ATK and no decent way to protect itself.
Best one can hope for is that Sera either gets a skill that lets you summon Constellar monsters without tributing, or we at least see Pollux and/or Leonis somewhere in the future. Otherwise, Constellars are best used as either fodder or filler for any other archetype.
And note: I'm talking about Constellar in their current state. For all we know, they could be adding in Pendulum and Link monsters eventually. Doesn't mean any related decks are good at the current time.
Agent of Creation - Venus can swarm for Light Ruler as well, and all you need to do is draw a single copy, rather than clogging your hands with constellations. Not too sure how viable Light Ruler is in the current meta, but something tells me it's not one of the greatest strategies.
This is just another of the archetypes like Infernity related to the characters that Konami released crippled and without the cards useful to run their engine. I mean, I dare anyone to play a competitive Infernity or Constellar deck right now