You see @juanmolina, when a blockchain game becomes popular (such as CryptoKitties has), maintaining its operation could require hundreds of thousands (and in some cases, even millions) of transactions.

To put it simply, there isn’t an existing blockchain that is able to maintain that type of load on-chain. When CryptoKitties first launched, it occupied a significant portion of the total transactions on the Ethereum blockchain. Due to this, transaction costs continued to rise, and when the game reached its peak of popularity, it pretty much rendered the entire Ethereum blockchain unusable.

Video games, like any major project, require a lot of operations going on in tandem, from concept, to development and beyond. The gaming system needs to have adequate enough processing power to render the graphics, meanwhile, the gaming system needs to able to seamlessly execute any actions the player wants to make. It's incredibly easy to fall short of this, exasperating and even resulting in players swearing off a game entirely, we see it in the mainstream gaming world all the time.

It is this complex structure that explains why most blockchain games are relatively simple in-game style from architecture to playing them. Many blockchain games operate with relative similarity to casual mobile games that we've seen in the past and present when it comes to their gameplay and appearance.