Some of the main activities in Animal Crossing are things like catching fish and bugs, and digging for fossils in the ground. These help improve children's attention and focusing skills.
Different events happen in Animal Crossing at specific times of day, and year, such as holidays or in-game events. Since certain stores open and close at certain times of day as well, these require children playing to manage their time, giving them a sense of responsibility as well.
Animal Crossing allows for immense creative expression, whether it be in their avatar, their home, or their island/town as a whole. This requires children to pick and choose specific items or elements and arrange them in a certain way to their liking along with creating original patterns or finding ones online to use. This requires a certain level of attention.
There are daily activities in Animal Crossing that are encouraged for players to do to ensure the upkeep of their island/town. This includes things like watering plants, picking weeds, and talking to villagers who live in your town. An established routine helps children learn to focus for longer periods, helping with attention spans.