Early on, pierce is quite valuable for Finn due to a noticeable lack of pierce on most characters without many star upgrades or trinkets. This makes it useful for clearing large groups of Bloons, making it ideal for new players clearing Normal Difficulty maps. However, it quickly falls off as soon as you start to clear Hard or Extreme difficulty maps due to the lack of damage to MOAB-Class Bloons, and so Peppermint Battle Axe or better should be considered instead.
