While I would normally not be excited about a card that has to tap to use its effect, a lot of care went into how this legendary creature was designed to ensure youre able to use it to its fullest
Self-Destruct Tournament Impact: Only one copy mainboard
The one granted by the new Nadu may trigger twice for each creature you control, even if the ability granted by the old Nadu already triggered twice for those creatures that turn
The Herald will keep you alive once you would lose the game, while also preventing your opponent from winning the game
I can see a lot of decks like Ranar the Ever-Watchful or Taigam, Ojutai Master as great use cases for this outside of this set as well, so it's going to have some good options on hand as well
Old Gnawbone, Kokusho, the Evening Star, and Galazeth Prismari are examples of commanders that happen to be dragons but arent great dragon commanders since they have no inherent synergy with other dragons