Doug Beyer was a creative director at the time and Jessica Lanzillo, the other creative director at the time, went, OK, OK, you know what
The crystals would represent natural elements
It's one cheaper, rarely stays around unless you want to spend 10 total mana, and then rocks flying and pro Black to block safely for the turn and is just one color
Whirlwind of Thought Im not usually a fan of nonland cards that do nothing when they hit the table, but Whirlwind of Thought represents an inexorable source of card advantage in many strategies that will win you the game if allowed to stick
Theres card draw and pressure, but more importantly, Yshtola works as a powerful value engine once you stack it with auras like Curiosity and Sigil of Sleep
For players who want professional proxy printing in Europe that holds up at any table, through any game length, the technical foundation is exactly where that confidence comes from.