Hey,

CCAs are important as it brings to life the qualities universities are looking for in students. Some of the qualities are highly relevant to academic potential or ability, such as resilience or creativity. It contextualises the qualities admissions officers are looking for and allows an applicant to stand out if a student is able to reach a high level in his or her CCAs.
While grades are still the most important factor, many unis are trying to portray that they are looking for more holistic and well-rounded students.