Here's why:
* Adjectives describe nouns: They provide more information about a noun by telling us its qualities, features, or characteristics.
* "What kind" asks for a quality or characteristic: For example, "What kind of car is it?" The answer will describe the car's type (e.g., "It's a red sports car").
Example:
* "What kind of music do you like?"
* "I like classical music." ("Classical" is an adjective describing the type of music.)