I am not sure where I suggested that a company is forced to use the system or not. I can't see any company testing their current employees as there is no advantage for them doing so. The would only be interested in the certifications of new candidates.

So your objection seems to be that a company offering these tests might make a lot of money by having lots of people take these tests? It is not like companies aren't doing these skills tests already - the nice thing about this approach is that it makes the whole testing process more transparent. As a candidate you know if you passed or not, which is more than can be said for the average whiteboard test.

Of course the tests would be specific to the skills you want to be tested on. If you want to be tested on front end material the test would be about that, not operating system kernels. The candidate controls what skills they want to be tested on.