There are variety of ways and methods a school can apply and practice competency-based learning. Below you will find some excellent websites discussing the benefits of CBL and how it can work.
https://explorance.com/blog/5-benefits-competency-based-education-students/
https://knowledgeworks.org/resources/role-teacher-personalized-competency-based-classroom/
https://www.gettingsmart.com/2017/12/competency-based-education-definitions-and-difference-makers/
https://www.redesignu.org/what-difference-between-competencies-and-standards#
https://aurora-institute.org/cw_post/what-is-the-difference-between-standards-based-grading/