Extreme Heat is good at eliminating high-health Bloons or Bloons that benefit the opponent when damaged, such as Weakening Gas Bloons and Growth Gas Bloons.
Extreme Heat pairs particularly well with It's All On Fire Now, allowing the player to set any Bloon On Fire and then destroy it with Extreme Heat immediately for only 5 Gold, and both cards have 2 charges.
Extreme Heat is an easy way to trigger the Volatile Bloon to heavily damage all Bloons on both sides.
With 2 charges and no possibility to return the card, Extreme Heat is better at stopping enemy bloons than Return to Sender, without any risk of giving the opponent extra sources of Bloontonium.
However, this is not to be used to remove an opponent's The Eternal, or else it'll scale further, unless the opponent's deck is already full.
Players who are seeking to boost their own The Eternal could use Extreme Heat to instantly pop it, along with Bloon Melter. To allow The Eternal to come back, always have 7 or less cards in the deck if using a 2-charge Extreme Heat.