Do you feel the same way if you're not wearing the latest fashion accessories?
If I encounter a person that is covered in tattoos I find it intimidating certainly. Similarly, a man with appropriate earrings and perfect hair and bright, smooth clothes also sends a message to my brain that they're confident and strong. It looks like there's a purpose to their appearance. They worked at it.
It's probably mostly psychological, and the people that care to do this probably have figured out that they can control people's perceptions of them and manipulate people in doing so. I cannot much be bothered to do that myself (couldn't if I tried), but obviously it is achievable and worthwhile for some.
This is how I picture you from what I know of you, though I'm not sure if I've ever seen pictures. I don't imagine that you just throw on a wrinkled T-shirt and sweat pants when you leave the house (I pretty much do).
Insert: I don't actually agree with "fashion" trends though so fashion by itself doesn't interest me. Until I met my finacee I used to dress completely backwards to usual fashion trends. Big, baggy clothes that were 4 sizes too large. Most people wouldn't have actually appreciated it. I didn't do it because other people thought it looked cool. I did it because I thought it looked cool, or because it gave me confidence. Now my finacee mostly chooses my clothes for me, and her liking it gives me confidence too since I know that other people like it. I would never have chosen it myself though if I went shopping alone (and I force her to find a balance that is comfortable for me).
But my intimidation from CSGO skins isn't because they're "fashionable". The interpretation was my own. It wasn't because other people were talking about it. It was because I was envious of it myself. If it's something that you don't know how to have, or cannot afford, then it is obviously something to be envied. At the time, I didn't know how to attain it. And even now that I do know, much of it is still out of reach because of the insane price tags (rarity).
Note that in CSGO there is no body language. Everybody takes the form of a few stock avatars and inherits their animations. The only differences are their actual play styles, and the skins they choose to have. The skins are actually valuable too, so you know that somebody that has really nice ones is either quite wealthy, extremely lucky (probably not), or sponsored.
My skins are impressive to the lower ranks and guys that have never dabbled in skins, but in reality most of them are dirt cheap and anybody could have them if they wanted to (except for kids without a credit card nor open minded parents). There's only a few skins that actually cost real money, but even those are affordable for any adult with a job. The really really nice skins are an insane investment. I'm talking about like $400 to change the appearance of your weapon in game. It looks awesome, but is otherwise pretty useless. These transactions are real things, and people really buy them for this kind of money.
I bought my knife for about CAD$90 about a year or so ago. Like most of my skins, it's pretty much the cheapest "Stat Trak" skin I could get, but knives are just more expensive because they're the "elite" weapon (i.e., respected because it's difficult to succeed with one). Looking at the price of the same skin now it looks like it might be worth about USD$90. That's about CAD$115 right now. So in that sense, my investment has actually gained value. Of course, as mentioned, I really cannot liquidate it back into cash. However, I like it, and it does get quite a lot of attention.
I've had countless people add me as friends on Steam only to make offers on it. Guys have offered to pay me $300 for it. However, as a precaution, I refuse all trade offers. Typically these kinds of offers are made on the "black market" i.e., outside of the Steam marketplace. Guys will offer to pay with e.g., PayPal or through third party sites or services. You can't trust those deals so I just avoid it out of caution. Honestly, why offer me $300 for a skin you could buy on Steam marketplace for 1/3 of that, unless you plan to scam me. And many people have been scammed by these kinds of deals.
It's ridiculous, and yet, it is very satisfying. The knife skins are the best ones. Not only do they change the appearance of the weapon, but they also change the shape and animations. They are effective in that sense. On the other hand, I don't much enjoy going "out" or doing the things that most other people do and spend countless money on. I predominantly play CSGO with my free time (I have logged 2441 hours in a little over 2 years). I could spend this money instead on other games, but I'd never get that kind of value from it (~$300 for almost 2500 hours and counting!?). It's actually not a bad investment when you think about it. A lot better than several items in my Steam library or in the real world that I regret purchasing.
And of course, I'm sure there are things that you spend money on that I would find ridiculous. Whatever makes you happy.