You can argue that mana is the most important resource in Magic, so getting more of it is one of the best game actions you can take
Ice Caves of Kzeldurad Plane: Nozgorod Whenever a player casts a spell, any player may pay that spells mana cost
A discarded card is such a cheap cost to get a Pest token, especially in reanimator decks
It inspired me to utilize World Championships Survival of the Fittest s for my first Premodern deck, and I was greatly thankful for the discount
The many cheap burn cards in red helped get the hideous, woefully flawed, Jackal Pup through, for lots of damage, when the seemingly much stronger white version would be scared, sitting at home, for fear of tussling with a 2/2 first striker or simply a larger creature
He also allows you to play Broom characters for 1 less Ink each, as well as returning a Broom character to your hand when its banished in a Challenge, instead of discarding it