The 61st card, definitionally, is going to be a worse fit than the cards that came before it when building your deck
Granted, a majority of them are only really peddling the most recent modern (as in SV and whatever else has been reprinted) with some token massively overpriced WOTC era and ex era stuff
Against a deck like "Trix" (Illusions of Grandeur + Donate) or "Aluren," that one less mana then it takes to cast Aura of Silence is vital
One actually requires a black light to see. In a brief FAQ section at the bottom of the listing, the seller states that they are unwilling to break up the set, save for an exception of the coveted and controversial Black Lotus card
This slightly slows the deck without touching its core
A deck that wants to play something like Siege Rhino might play well with other powerful fighters like Fleecemane Lion or Tarmogoyf