Think of them as shelves in a library
A type of MTG card that Wizards of the Coast is really happy to print, there are well over a couple thousand token generators when you consider all colors, and hundreds of them are pitch-black
Then, anytime you are tempted by the ring, you can discard your hand, both filling your graveyard with fuel for explosive later turns, and keeping your hand fresh with new cards
As that trigger resolves, the battle is exiled and then the back face is cast without paying any mana cost which is handy as the back sides dont have mana costs, anyway
Bonus fun fact: the moth-circle-moth loop came from looking up silkworm moth cocoons: when seen from the right angle (like here), they fit right in with moth wing pattern aesthetics
Despite this rather substantial drawback, Exploration is still an incredibly useful card