Panharmonicon itself never actually triggers, it simply means anything that triggers from a creature or artifact entering the battlefield will trigger again
How could you not fall in love
Free cards are so much better than cards you have to pay for, and being able to land this on turn five (or earlier) is sure to make you a target, but could also make you unstoppable
If you love enchantress decks, then Tuvasa the Sunlit might be your choice, or Syr Konrad, the Grim if youre a graveyard player
See for yourself: I dont know about you, but I think the art on some of these cards looks awesome, especially The One Ring, which is listed as an indestructible artifact
If your goal is polymorphing your own creatures, I urge you to try this red human soldier