Indeed L2 on pc, and since 2017 on mobile is inspired by Gacha mechanics (Gashapon) from japan. Gacha is a good F2P monetization strategy. Gacha mechanics should be designed from the start (concept, prototyping, etc.), not added during production or after the game is released.
Ingredients to get it right, including:
Vast and varied content
A strong desire on the part of the player to collect as many items as possible
A game where content is needed for players to progress
An effective mechanism for duplicate content (to prevent player churn rate from pulling too many duplicates)
Pokémon Go is an example of the successful westernization of Japanese gacha mechanics. Gacha works best when there are rare items that are specifically more powerful and highly desirable. Gacha also works well when it focuses only on collecting.
But gacha can be even more powerful if the virtual elements provide a competitive advantage.
If there are more mechanical and progression-based perks attached to a gacha (for example when a 5-star character is critical for high-level play), you will monetize higher on a per-player basis. However, in this case the risk is that l2 alienates some of these players.
A measure took effect on May 1, 2017 on the official website of the Chinese Ministry of Culture,
I quote :
"Online game publishers shall promptly and publicly announce information about the name, properties, content, quantity and production / production probabilities of all virtual items and services on the official site or on any site probability of drawing in the dedicated game. The information displayed must be up-to-date and correct.
“Publishers of online games must publicly announce results by users on visible sections of the official site or in-game, and must keep a history for the government. History must be kept for 90 days or more. Taken to protect the life this cannot completely prevent publishers from doing what they want, but this decision remains a real step in the right direction, especially when we see the drifts that can bring the whole economy of virtual objects which is worth billions, and knowing that the algorithms can be modified.
The legislation on this regularization and the transparency of these games takes a long time to be put in place, and in some countries this practice is prohibited. Some countries are more flexible so cannot be imposed everywhere.