What's different in the bonus card is the text on the card, and it was exactly what players wanted
Chan did an excellent job capturing Nyx, the starry realm that exists within Theros night sky, while also having dynamic action
For example, [c]Kess, Dissident Mage[/c]s color identity is blue-black-red, because its mana cost consists of those three colors
Personally, I think its a fun and interesting way to play the game on an unusual axis, though I can see why players wouldnt like to see their beloved cards disappear before their eyes
Similarly, those who are already irradiated tend to get more irradiated
Now I know a card being the first creature with a casting cost of XX may not excite all of you, but it makes me smile