Power Points are a special currency used to upgrade Brawlers.
Using Power Points
Once you have enough Power Points to the specific Brawler you want to upgrade, you can finish the upgrade with Coins.
Obtaining Power Points
The most common way to obtains Power Points is by opening Brawl Boxes.
You can also purchase them directly at the shop using Coins, but this is a dangerous practice as you might not have enough Coins to upgrade your Brawlers later