First, cats and dogs differ in many ways, such as their habits, appearance, and personality. These differences are precisely what cause them to differ in terms of popularity among humans.
First, in terms of appearance, cats are generally smaller, more agile, and more aesthetically pleasing than dogs. They also have a wider variety of coat colors and patterns, making them more attractive. In contrast, dogs have less variation in size and appearance, which may make them less likely to attract attention.

Secondly, in terms of temperament, cats are generally more independent and self-reliant than dogs. They don't require as much training and socialization, nor do they need frequent companionship and care. Therefore, for busy people, owning a cat may be more convenient and less stressful than owning a dog.
Third, in terms of lifestyle, cats are better adapted to city life than dogs. They require less space and are more suited to the environment of high-rise buildings. Also, cats eat less than dogs, making them potentially more suitable for people living in smaller spaces.