Skill is good and educational certificate is also good. Having any of them can actually put food on your table, but the question is which of them will you let go for the other. I mean education can get you a white collar job the same way a skill can too. For me i will let go of the skill because skill without basic education is not good at all. Because I have seen a situation whereby a guy with good skill who got a job was unable to give quotation and he lost the job .Formal education is good for everyone.
Having a university diploma(or as you call it "educational certificate") is simply a proof to your employer, that you have passed a series of standardized tests and qualifications. The certificate itself doesn't "put food on the table". The certificate simply proves that you have certain skills. You could acquire those skills without getting a certificate, but there must be other ways to prove to your employer, that you have skills. For example you could have a design portfolio, or you could get recommendations from your former employers.
I've seen many cases of people buying fake diplomas in my country. This doesn't make any sense to me. What's the point of buying a fake diploma/fake certificate, when don't have skills and your future employer is going to find out, that you are incompetent?