Here's another way to put it by way of analogy.
How can you tell if someone is fashionable or well-dressed? Do you need to see the "Armani" label to know that it's a nice suit? Do you need to see the "Church's" label on the shoe to know that it's a finely crafted shoe? And more importantly, do you need to know at all whether this person spent thousands on every piece of clothing on his body to sense whether this person knows something about grooming and fashion?
To someone with no fashion sense or aesthetic, they wouldn't know the difference and couldn't tell. But to those who are experienced in this (i.e. fashion editors, designers, etc), they don't need to see the brand names to know whether the guy has fashion sense or not - and whether the clothing he is wearing is of high quality or not.
Same with the adcoms. They don't need "certifications" to get a sense whether you are accomplished or not - and whether these accomplishments are of real substance or not. Having seen hundreds if not thousands of applicants, they can get a sense of it pretty quickly without having to see certifications, gold star stickers, ribbons, etc.