In the same way that randomness in a roguelite leads to you feeling really good when you find an item that is cool and that you didn't expect to get, you have that same mechanic taking place when you either save enough in-game currency or use real money to buy a new lootbox and get a new item/character.
It's a different mode of accessing gameplay that is random, and just like in a game that abuses this mechanic to keep people playing for hundreds of hours (roguelites), these mobile games also do that, except with the possibility of paying real life money.
It's a different mode of accessing gameplay that is random, and just like in a game that abuses this mechanic to keep people playing for hundreds of hours (roguelites), these mobile games also do that, except with the possibility of paying real life money.