While players do need to strategically choose which cards they are going to discard, some decks play enough energy to the point that the choice is an afterthought, and extra energy is the choice every time
Did you remember this mechanic
Eldritch Moon Release Notes Compiled by Eli Shiffrin and Matt Tabak, with contributions from Laurie Cheers, Carsten Haese, Zoe Stephenson, and Thijs van Ommen
Most of the Jeskai Tempo decks only play two copies of Sarkhan, the Dragonspeaker as their planeswalker with the occasional deck playing one or two copies of Chandra, Pyromaster along with Sarkhan
Given that the drop containing it is sold out already, it will likely be incredibly expensive as a result.
They are the foundation of the game, with basic lands being used to tap for mana you'll need for everything else