These have additional, unusual effects
5D's , Yugo stated that dueling is the fastest way to create a comfortable life for yourself in the Synchro Dimension, unlike Standard, which is treated more like a sport than anything
(From WOTC) Planechase, also known as Planar Magic, is an official game variant first populated by Planechase (2009) and basically acts as an augmentation to other formats though players can also play decks specifically geared towards this format
By narrowing down an identity for each Commander deck, not only do you guide yourself toward more affordable, fun and personal card choices: you create new goals to chase in-game which align more closely to your idea of fun than the often-political question of overall victory
Imagine doubling up on Kolaghan's Command or Drown in the Loch: Suddenly your interaction is overwhelming