It's not just evident in the usage of currency

It's not just evident in the usage of currency that is paid for items however, D2R Items is also evident in gacha mechanics as well as in the public disclosure of drop rates for uncommon items. Gacha is the act of using in-game currency whether it was free or purchased from an in-game shop to acquire something random objects, in the case of Dissidia Final Fantasy Opera Omnia or characters from the ever popular (and persistant) Fate/Grand Order or Genshin Impact.

In the case of Diablo Immortal, you can use the Legendary Crests (which can be bought or earned) in order to increase the probability of a five-star gem showing up in endgame dungeons. While it's not exactly traditional in its approach to presentation (most gachas involve "rolling" on a time-limited banner) Players are engaged in the same kind of randomness that they are used to in other games in the same manner. In many ways this is how it's like the Diablo brand has been working towards these types of mechanics from its beginnings as Maddy Myers wrote a few weeks in the past.

Diablo Immortal also, in the simplest terms, takes direct inspiration from a "feeding" method that many Japanese, Korean, and Chinese mobile games have adopted for over a decade. "Feeding" is the process of increasing the attributes, stats, or the rarity of an item by making duplicates of a drop. The duplicates then feed to an item of similar rarity, which increases the overall stats of said Diablo 2 Resurrected Items . Generally there are five copies according to industry standards to max out an item or character.