Thoughtcast, the only card with the actual affinity mechanic that still sees regular play, is kind of like the glue that holds the deck together
While Rhys the Redeemed helps build your forces with its first activated ability, youre mostly interested in the second ability that doubles your tokens
This cycle is nasty in Type Four (rules for it here - Type 4 - MTG Wiki (fandom.com)) where you have infinite mana so their casting cost is not a problem, but you can only cast one spell per turn
That means burn spells shrink blockers instead of just dealing damage, and spellslinger commanders that were already copying spells are now doing it with a 6/6 in the air
Each card is so incredible that the more you have, the more you can potentially warp the game to your benefit
The Matchups Defenders struggle most against removal-heavy control and midrange decks