Players get around 75% breifcaes and 25% keys.
Player are supposed to buy keys.

Buying a N-Gacha on Japanees servers give playes a free N-Key (pink key). Even if bougth with Peros.
Buying R-Gacha, SR-Gacha, E-Gacha give free R-keys, and SR-Keys, players hav to spend gold to get those.
So all N-Briefcases get open but most R- and SR-Briefcases dont get opened at Japanees servers.