Well, then following your logic any qualification can be link to any job
I wish INZ had your way of thinking.
Here is what Operational Manual states in regards to relevance of qualification to employment:
Qualifications are relevant to employment if:
a. the major subject area and level of the principal applicant's recognised qualification is
directly applicable to the employment;
and
b. the immigration officer is satisfied that the qualification was a key factor in the employer's decision to employ the principal applicant in that position.