In the case of Diablo Immortal 2023 from Devon's blog

It's not just evident in the use of money for items however, it is also evident in gacha mechanics as well as in the information about drop rates in more rare items. Gacha is the practice of using game currency Diablo IV Gold, whether it was free or purchased by a shop in the game, to obtain something at random like pieces of equipment in the case of Dissidia Final Fantasy Opera Omnia, or characters in the ever popular (and persistent) Fate/Grand Order or Genshin Impact.

In the case of Diablo Immortal, it's the use of Legendary Crests (which can be purchased or earned) to increase the odds of a five-star gem showing up in the dungeons and dungeons endgame. While it's not completely conventional in its presentation (most gacha are performed by "rolling" using a time-limited banner) the players are engaging in randomness that they are used to in other games in the same manner. In many ways in many ways, Diablo is a classic Diablo franchise was working towards these types of mechanics from it's inception as Maddy Myers wrote a few weeks back.

Diablo Immortal also, in simple terms, draws directly from the "feeding" method that Japanese, Korean, and Chinese mobile games have adopted for over a decade. "Feeding" is the process of increasing the stats, attributes or rarity of an item by making duplicates of a drop. These duplicates are then fed to an item with the same rarity in order to increase the overall stats of said item. In general there are five copies as a standard for maxing out a character or item.

My first exposure to "feeding" was Fate/Grand Order, which was first made available to Japan in July 2015 and brought in a total of $4 billion dollars globally in the year 2019. In order to create the most memorable character it could absolutely be I needed duplicates of every character. And when a particular banner rolled around I paid upward of 300 euros to get the five-star character I had coveted all my life. However, I never obtained the replicas I needed to be able to appreciate this character's full potential. Since the rate for the highest-rated 5-star characters sitting somewhere at one percent, it's not a surprise that I failed to acquire a copy the character while engaging in this game (which I have since uninstalled) cheap Diablo 4 Gold. As of the end of July, 2021 Fate/Grand Order was the seventh highest grossing mobile game all time, putting it behind Konami's Puzzle and Dragons, which, I might add, is also a gacha-based game.