Alternatives for "demand"

I think you've veered a bit toward the end of your question from what you'd initially set out to ask, which is:

How do you write the above sentence, when familiarity with Z is not necessary, but helpful as part of Y?

In which case I suggest rephrasing the sentence thus:

Familiarity with Z facilitates Y.

Or perhaps,

Familiarity with Z nicely complements Y.

I hope you realize this is different from Y leading to learning (about) Z.

The cause-effect relationship is inverted in the latter.

“I have worked as X and Y. The job Y benefited from familiarity with Z."

Benefit = to be helped by something or to help someone

Cambridge dictionary