No belt should be issued too readily.
To give a belt to an unworthy student insults the individual and brings shame to the school.
Each belt should carry with it the expectation of a higher standard.
Black belts in particular must be awarded cautiously; and only to students who can truly express the art and have put in the necessary years of practice.
If an art offers many belts, then it should be because the syllabus is lengthy, sophisticated and requires a step-by-step approach to learning.
Not because it is a gimmick.