I spent a lot of time during my PhD (that lasted exactly 3 years) resisting whatever my adviser said. He had a clear plan for me to graduate on time, but I was the one who did not believe that I could meet my graduation deadline. As a result, we argued a lot.
Once we were arguing about my scintillating academic life (or the lack of it) and how much coursework would be enough to make me a desirable PhD candidate when I start job hunting. We started our conversation about job hunting pretty early, at around 6 months when students were still comfortably settling in. “I never want you to feel comfortable or settled in. That way, you will never graduate,” he said bluntly.
We were arguing because my adviser wanted me to take as many methods courses as I can. Being able to analyze and interpret data is vital in my field. I think I eventually took 5 levels of statistics courses and 3 levels of qualitative methodology courses alone other than the core courses and a mixed-methods class. I made a face and told him that I do not want to drown in methods courses, that I would learn on my own or take online classes later. To that, he gave me a great analogy that I will paraphrase because I found some wisdom in what he said.
In graduate school, we are like a computer processor in the making. With new courses, we get to learn new skills and thereby build our processors. Our configuration is constantly improving. We get to take classes, write exams, get feedback (through grades) and interact with peers which is great way to learn new skills. By the time we are out of grad school, the features in our processor are set. It is not malleable anymore. Sure, we can go for an external upgrade, adding a feature every now and then by auditing a class or attending a conference. But these are external features. The core has already been built by then.
Graduate school learning builds the core, the inherent qualities of a researcher. Therefore it is important to take every remotely relevant methodological course, write exams (and not just audit courses), and learn every new skill we hesitate to learn (because we are too afraid to fail) fooling ourselves into believing that we will once we get a job. Graduate training is the only chance to build the processor from the scratch. The rest gets added along the way. One can afford to skip a "Writing literature review" class because that is a skill one can pick along the way. However, one cannot afford to not take a class on methodology. So go take that class because it is free and paid for, and because once you graduate, you will never get to take a class again, not this way.
I don’t understand much of computers or technology (other than what I need for work), but I loved this analogy. Years after finishing graduate school, I see the value in what he said. No more arguments after that, I buried myself building my processor, and I have not regretted it. Although I do not apply the methodological know how in everyday work life, I know enough about it to be able to navigate my way around. For example, I do not dabble with differential item functioning or item response theory every day. However, when I read a paper that did those, I do not have the deer in the headlights look. I exactly know what they are talking about.
Listen to your adviser (not blindly though). For he may be as clueless about your future as you are, but given his vast experience, chances are less that he will give bad advice.