One thing that comes to mind is job interviews. When you apply to, say, a surgeon opening, certification and previous job experience is enough, no one asks you to perform homework surgery or list all the bones in human body.
True, but still, it's not like you are going to say "here's my github, CS diploma and references from previous jobs" and hear "alright then, let's skip reversing those red-black trees on a whiteboard for 4 hours, welcome aboard".
I understand why those are not enough, but it would be nice not to have to prove you are competent from ground up every time you want to change a job. Hence, certification, etc. But I have no idea how to do it well, though I do hope someone else spends couple of years figuring it out :)
