This is just one of those cards that should be in any deck with flicker effects in them
On top of that, Emrakul never had to exist in a format with powerful graveyard hate along the lines of Rest in Peace, Leyline of the Void, or Scavenging Ooze, and the presence of those cards gives opposing decks much more ability to fight back against Emrakul
Each triggers one or more of your commander's abilities which add additional scry, creature tokens, burn, and can buff your army
The ceiling is not quite as for Arc Trail high but is none the less surprisingly close and more importantly it is much much easier and more common to reach or get near that ceiling and early in the game too
Its certainly a card that Im keeping my eye on right now, but I just dont see it
It also doesn't matter if the opponent you attacked is still in the game