The price oracle's purpose is to balance the $ETERNAL payout gained through mining, along with minting costs to the current dollar value of $ETERNAL.
This means that the following will happen if the dollar value per $ETERNAL increases:
$ETERNAL payouts decrease
Mint Spaceships costs less $ETERNAL
Mint Workers costs less $ETERNAL
If $ETERNAL price in dollar decreases the opposite of the above becomes true.
The Oracle will dynamically adjust costs and rewards up or down depending on changes in the dollar value of $ETERNAL.
The reason for the oracle's usage is so that the economy of the game is balanced around a set dollar value. A limited amount of $ETERNAL token that can circulate in the economy, and a big influx of players would likely drain all the $ETERNAL present in the game contract.
By utilizing the oracle, CryptoMines forms a correlation between active users and the dollar value of $ETERNAL. The assumption is that when the $ETERNAL price rises, the demand for $ETERNAL increases as well through the release of new game features or an influx of new players. The oracle will ensure consistent dollar value payouts per transaction at the time it was made, along with ensuring mint costs for NFTs remain at a consistent dollar value.
This means that entry costs and rewards can be balanced and maintained for extended periods of time, and will accurately reflect the desired minting costs to allow new players a chance to play even if the dollar value of $ETERNAL rises.