Loot boxes work by having a list of items with weighted probabilities adding up to 1, and what you buy is getting one or more of those items at random. The way

Loot boxes work by having a list of items with weighted probabilities adding up to 1, and what you buy is getting one or more of those items at random. The way the weighted probabilities list is constructed changes from implementation to implementation. The prevalent one so far is "box gacha", the spiritual successor to "complete gacha". The latter is now banned in Japan and the rest are somehow regulated. The motivations are many. First, it distributes large payments over smaller payments making people lose control over their spending. Then, it complicates people's perception of how expensive an item is. In a sense, lottery games are the same in spirit. For example, what's the probability of getting an arbitrary unique combination of 6 numbers out of 49 (lottery)? Very, very low. https://en.wikipedia.org/wiki/Lottery_mathematics https://en.wikipedia.org/wiki/Lottery_mathematics In mobile, they're usually coupled with "events" that have a leaderboard. Events are actually auctions were people "play" (bid) for a better place in the leaderboard. The rewards are usually not worth it, because through successive updates they're made worthless (e.g.: stats inflation).