> I don't make that assumption, lets keep it simple and assume it's just a cosmetic display item without any abilities and that it's possible to display this item in the other game.
Since it costs thousands of dollars to store any significant amount of data on the major blockchains, any game item will just be some reference stored on the blockchain.
Unless every game developer builds an appropriate model for every possible item there's no "simple" importing of an asset. Even if a full asset was shared between games no two games are guaranteed to display even a texture the same way.
Even your example of "rank" is meaningless. Rank in one game doesn't have anything to do with rank in another game. The number of goblins you killed in a fantasy RPG has no meaning to a racing game.
As for these being scams, there's no reason any of these things require a blockchain. Games have at various points supported custom player models, skins, spray decals, and all sorts of other shit. None of it needed the added rent extraction of a blockchain.
The only reason to add a blockchain is to get players to prop up whatever shitcoin blockchain is being used. They get vague promises of asset reusability but actually just get normal scammy in-app purchases.