My answer: yes for writing stories.
If I had to write about auditor's life, financial statements, business processes, crochet, game development (especially the concepting process), and other things I personally ever dwelled, I'd put in specific details that people outside the field may not know. For me, it gives out different feeling from only watching or reading references. I can always writing from watching/reading references, but those who are really in the field knows.
If you have the time and money to go to classes, do it! I agree with swordfighting you mentioned. When you learn for real, you'd know the details you missed when you only read/watch references.
About writing the skill that I know, I haven't really try to write anything related to skill that I know. I don't want to write a novel, or even short stories about my job (most of my skills, well, what I acquired for daily job). If we're talking about crochet, I can't draw someone crocheting even I have been doing it for years
this also applies to holding a pen!