It’s fair to the country as the country is able to make informed admission decisions weighted by the needs of the country, rather than a take-all-comers model.

It’s fair to the applicants as they have a clear set of guidelines as to what they need to do to become eligible for admission. Need to learn English to boost your score (As in Canada)? Cool. That’s tangible and clear. On the other hand America’s system of, roughly speaking, “Indians need not apply” isn’t exactly fair to the applicants.

Note: a points based migration scheme doesn’t preclude for instance refugee admissions, and Canada’s system has a points escape hatch if a province nominates you based on their specific needs too.