Why do Countries have Major College Entrance Exams?

From what I've seen, a lot of countries globally have some sort of hard college entrance exam. Why is this the case? Do colleges in these countries generally not consider other aspects of a student's application as much? Any input would be appreciated!

Major college entrance exams are used by various countries as standardized measurements to assess a student’s readiness for higher education. These exams, such as the SAT or ACT in the United States, the A-Level exams in the United Kingdom, the Gaokao in China, among many others, play a significant role in the admissions process in many countries, often serving as objective yardsticks to compare and evaluate applicants across the board.

From an administrative perspective, these exams are used to gauge the academic prowess of prospective students in core subjects. They are believed to provide a standardized means of assessing an individual's potential performance at college and are particularly useful in comparing student proficiency across different educational systems and regions.

However, the weightage given to these exams can differ from country to country, and even from institution to institution within a country. Some countries or universities might place a higher emphasis on the results of these tests, while others might take a more holistic approach to evaluations, taking into account a broader range of factors like the student's high school coursework, grades, extracurricular activities, personal essays, and letters of recommendation.

In the United States, for example, while standardized test scores like the SAT or ACT are significant components of the application process, many institutions utilize a holistic review wherein factors like grades, course rigor, extracurricular activities, personal essays, and letters of recommendation are also substantially considered. Conversely, in some countries like China, the National Higher Education Entrance Examination (Gaokao) plays the most dominant role in college admission decisions, oftentimes carrying more weight than any other portion of a student’s application.

These variations in considerations for college admissions are typically rooted in each country's education philosophy, logistics, and historical precedent. While standardized tests can provide one uniform measure of comparison across students, a more holistic admission process might allow applicants to present a well-rounded picture of themselves beyond test scores.