how is a bit of paper supposed to show your "skills"? And even then if you could show your skills in a CV it'd take a while to write and read, why bother when you can just look at the grades of 100 applicants and get the best of that?
If you genuinely think that Exam grades show nothing then you're probably only an advocate for that stupid mindset because you're one of the people without any. Exam grades don't always show how good you are at a job, but if an employer sees my CV, we both have no experience but i have 6 GCSES and you have 0 i'm getting the job, simple as.