In decks like Ad Nauseam + Tendrils, the card is used either to get enough storm count by drawing free spells or to find your Tendrils of Agony win condition
Isochron Scepter can't imprint Far // Away or Bound // Determined
For example, when you take your beginning phase, you'll have an untap step, an upkeep step, and a draw step, and then the next player in turn order will take their beginning phase
Even if you are so heavy on discard that you can have this always be vindicate you would probably still rather other bounce as you will more than likely have spare discard effects
This usually means theyre on the lookout for the most useful cards to use in play, and this often means the most powerful, too
Decks are also very consistent in this format, which leads to more even games, as long as each player starts a playable opening hand