This is one the most anticipated features for Brawl coming in 2023, players are really looking forward to this one
There are some reasons why this feature is very much necessary, this is because after removal of boxes from the game. The currency is pretty messed up as now players do not get much coins as they used to get before.
Plus, addition of new power levels which takes a lot of coins. You need to get supers and gadgets to buy from coins and they cost 2000 and 1000 respectively. But according to brawl team point of view this gives longevity to the game which is necessary as the game is Free.
Moreover, rewards in Masteries are going to help a lot. We can get coins and maybe even gems from it. But overall, the rewards are going to make the economy better.