HKIAAT Certified Accounts Clerk qualification有冇用嫁?

That's no use either working or studying.
If you intend to work in accounting field, you must continue studying and getting more certificates, such as LCCI, PBE, QP, ACCA, etc.
If you take this certificate during interviewing, most employers will treat it useless.
Seems you are so young, continuing study is the most suitable way.