There were several instances recently which somehow prompted me to think about clothing and what they mean. See, my spouse had began a new job lately, where these things matter. This is an environment where one is sometimes told to be dressed Business Casual. Come to think of it, I also had an interview a while ago when I was told to appear in Business Professional. And while I don't necessarily agree to these rules, sometimes it does matter, and it is just one of those things you just have to follow.
As a former academic, I find clothing not the most meaningful aspect of life to pay attention to. Academics would rather be judged based on their CVs and research output, rather than their clothing. I remember one day years ago, perhaps more than a decade ago, when I attended a dissertation defense of someone in the department. The dissertation was fantastic, yet the person was just dressed super casually, with even perhaps bread crumbs on his sweater. It totally didn't matter, since he was being judged not based on his outfit, but based on his research.
I work for a tech company, and I must say I am fortunate to be in an environment where how you're dressed does not matter. We're free to be, as they say.
But in others, clothing does make a difference. If you're facing a client, then you might want to dress one level better than your client. After all, clothing nevertheless conveys meaning, and if you are presenting to be an expert in your field, then your clothing should indicate that you know your shit.
I was in airports lately, where I saw people working inside the airports or in airplanes. They wear suits, even though sometimes they're running around the terminals and perhaps even the tarmac. But nevertheless, they need to convey the image that they are safe and trustworthy, so they have to wear a suit.
First impressions do matter, and it is very hard to control what people would associate you with when they see your clothing. So for some roles, it is definitely a big deal to dress conservatively. Thankfully, what I currently do does not require that, but who knows, maybe this would change in the future.