After all, you cant win until you dont lose
If a creature is put onto the battlefield attacking (thanks to Hero of Bladehold, Preeminent Captain, or the Ninjutsu ability, for example), that creature's controller may choose the defending player or planeswalker that it will be attacking in the normal way.
If you jam your entire deck full of the most expensive and devastating cards you can think of, your first big cascade spell has a good chance to do something game-winning
Lorehold, the Historian Dragons are more playable if they can immediately impact the board
So we can run Urborg, Tomb of Yawgmoth in our Darien deck so that Karma and Royal Decree deal damage based on all the lands in play
While the difference seems inconsequential, it matters greatly