Why should you use pug mixin and not include?

Question

Pug

Good afternoon! I am studying the issue of improving my starter template for projects with pug, the question has come up: why do so many people use only mixins and not includes when connecting to a page? I understand everything about the advantages of mixins (that additional parameters can be set and all that), but why are many blocks even WITHOUT parameters still connected by mixins? And in fact, we have an extra line in the code (first, the mixin include, then we write the mixin itself instead of a simple include). What's the point?:)