The Diablo Immortal game has a myriad of options for upgrading, currencies, and Diablo IV Gold reward systems, legendary gems are where the business model gets bitten the most. Blizzard and NetEase have not been so outrageous as to sell directly using a loot device or gacha, however, what they've created is, in a way, even more alarming.
Legendary gems are only dropped by the bosses of the randomized Elder Rift dungeons, and you can only ensure an infamous gem drop by applying an epic crest modifier the dungeon prior starting the dungeon. In other words, the rates of drop for gems that are legendary are very low.
Without spending any money on the game, you can only get one legendary crest each month. Even buying one of the battle passes will reward you with one or two additional legendary crests each month. Then, you'll have to buy them on your own. Legendary crests run approximately $2 and $3 for each.
The large number of gems you will need for your character's best equipment especially when you consider the very low drop rates of gems with five stars, is the reason why the price of maxing the character's stats on Diablo Immortal has been estimated as between $50,000 to $100,000 or more in the event you get into the system of gem resonance. (Rock Paper Shotgun is an extremely thorough breakdown of cost which is on the more conservative end of this scale.)
Diablo Immortal has been given an exceptionally rough ride for this business model (perhaps disproportionately), considering popular free-to-play rivals such as Genshin Impact and Lost Ark are hardly free of similar gacha mechanics to lure in huge-spending "whale" customers. Diablo's popularity and fame with an established PC gaming community, built up over the span of nearly a quarter century, is definitely one of the reasons. It's also the case that Diablo's system is extremely problematic, and the very nature of Diablo games could have something to do with that.
When you purchase legendary crests, it is not buying a set of the dice, as you do when purchasing the FIFA Ultimate Team card Diablo 4 Gold buy pack such as. You are purchasing a chance to roll the dice to reach into the game engine to tweak the drop rate (slightly) in your favor.