"Its a cash cow"
Its good to be skeptical, but in this case it really isn't. There isn't a mountain of money to be made in certifying people at this scale compared to getting certified in MS or Adobe software. The scheme really is a response to companies wanting a quick way to know that someone they are hiring is at least competent to a certain level.
Yes, portfolio is king when it comes to being hired or not, but a portfolio can have been made over an extended period of time; a timescale which just isn't commercially viable outside of a hobby. We've had this problem ourselves when hiring. Someone looks great on paper, in theory has years of experience, has some ok looking stuff to show; but when they get down to it, they're clicking around like a dolt that has never really used the software and takes 10x longer to do anything.
The certification isn't there to make a load of money, or to teach the artist, its there so that someone can get a job more easily. Its in its early stages but it has to start somewhere.
Regarding your specific fail reasons, obviously I don't know the details, but was it a case of not using enough shortcuts or not using shortcuts at all? If you use no keyboard shortcuts, then you will be measurably slower than somebody who does. Perhaps you know where every command is in the menu, but you've still got to navigate there.
I would expect at the absolute minimum for somebody to be using the basic os commands such as copy/paste. I would sincerly hope for them to use navigation shortcuts. I know people that don't, and whilst their work is fine, watching them work is honestly quite painful. Imagine a video editor not hitting the space bar to play and pause a video, but instead click the play and pause icons every time. Or who doesn't know how to cut a video clip without a text menu.
Which tools are you referring to when you say you'll fail because you don't use the tool enough? there are naturally basics which everyone need to know, im curious if there is genuinely something in the test that is too difficult.
Re: rigging tools, Every character animator needs rigging tools, but not everyone who needs rigging tools is a character animator. A cable needs rigging tools for animation for example