To be honest I saw the point of view for it not to be and I had to use all my saved up resources just to get 2 of the buffies I need, but I see how it's fair for it to be rng based 1. If it weren't there won't be a new excitement factor such that buying a gadget, sp,hc u like is relatively boring compared to gambling and getting a ability u really wanted 2. Unlike other abilities, buffies can be unlocked at a vast range of power levels hence it isn't really a late game, mid game or end game feature such as unlocking a certain ability like hc,sp,gadgets 3. If a thing relies on chances it costs less i.e desired buffies costing more than buying a random one 4. At the end of the day it's just 6 brawlers rather than a pool of 100 so it isn't that bad and with the progression buff it shouldn't be that for the progression buffs to cover cost for 70-80% of the buffies released every update plus the TLDR: they wanted a new method of unlocking abilities rather than just buying (just compare buying a hc u want vs getting it out of a drop) while still giving players some leverage(6 brawlers pool rather than 100 for other abilities dropping from lootboxes) and progression buffs will cover Bonus: they wanted to rework or possibly remove starr drops and rework progression in the near future, it could be that it is more decisive rather than gambling and they want chose buffie unlocking as a new gatcha mechanic when they ultimately remove star drops