With two different Battle Passes, both with Diablo 4 Gold specific rewards that are unique to a particular character (and not the entire roster), and too many different currencies available for the average player to track Diablo Immortal's financial system reads like a huge mobile marketplace.
The practices, even if they're opposed they have been accepted as normal within the industry at large. It is possible to argue that the popularity of loot box or other real-money transactions within AAA games has contributed to this kind of precarious economy. However, the more that AAA gaming shifts towards the games-as a service model, there is more in common with portable games which have existed in this highly popular area for more than a decade.
This isn't only evident by the use of paid currency to acquire items such as gacha, but also in gacha mechanics as well as in the information about drop rates in more difficult items. Gacha is the act of making use of in-game currency, regardless of whether it's free or purchased from an in-game shop in order to get something you want: pieces of equipment, in the case of Dissidia Final Fantasy Opera Omnia or characters from the ever popular (and long-running) Fate/Grand Order or Genshin Impact.
In Diablo Immortal's case, there's the usage of legendary crests (which can be earned or purchased) to increase the odds of a 5-star gem appearing in the dungeons of the endgame. Although not all that traditional in its way of presenting (most gachas are played out by "rolling" in a time-limited banner) it is still engaging with randomness in the same way. In many ways this, players are engaging in the same way. Diablo franchise has been working towards these sorts of mechanics since its beginning, like Maddy Myers wrote a few weeks ago.
Diablo Immortal also, in no uncertain terms, pulls directly from an "feeding" method that a lot of Japanese, Korean, and Chinese mobile games have adopted for over 10 years. "Feeding" involves raising the attributes, stats or rarity of an item through creating duplicates of an item drop. These duplicates are then fed to an item with the same rarity , thereby increasing the overall stats of said item. Generally, five copies are necessary to buy Diablo IV Gold max out an item or character.