One can invent/justify/rationalize any design element, no matter how absurd (eg. The utility belt is a lighter color so that Bruce is able to see it more clearly in the dark). These sorts of rationalizations are clearly absurd justifications for visually dynamic design choices (static mask covering face w/ exposed, clearly human mouth when one wants to appear as a creature? bat emblem on chest neither bright nor attention drawing? And on and on).
I know you have, but I asked "what disadvantage a gold belt presents". Similar to what is the actual advantage a bat emblem (neither bright nor attention drawing) on his chest is.
Unfortunately you haven't presented any argument as to why a gold/yellow/bronze belt present a tactical disadvantage yet.
I'm not going by what he said/presented- Not what I think he might have meant. Whether that was his actual intention is unknow, but I see this exact behaviour on these boards a lot. An observation.
The cape, for example allows him to fly and protects his entire person from various things such as flame or chemical, certain light, it even allows for certain arts of cape infused martial arts depending on it's weight....all seem pretty significant. You suggesting such justifications are on par with allowing him to see the belt better in dark

A belt he more often then not doesn't even look at when he retrieves it's contents, more than half of which are in his rear(see hawkeye/green arrow paradigm). Various stories of him telling other people where to find things on his belt; 'third compartment on the right'....sorry. That would be what you are describing as a flimsy rationalization.
I would ask you either try for a more significant rationalization or move past the point.
As for the mouth exposing that he's human, the batman is said to be some sort of creature, given the musculature/organic armorskin, some form of human hybrid creature, I'd even venture to suggest how often the alley shadows conceal the mouth(even more when he uses the useless cape) but that would be reaching I suppose. There are even a few stories where people mistake the actual man bat creature for him.. People think robocop is a hybrid..I digress.
Either way, Batman's mouth is exposed just as his joints are, he protects what's most important, further an exposed mouth presents a hand full of advantages(as I've also listed prior). Especially when he has various devices that can easily cover said exposure handy.
I haven't addressed it cause you only started asking. I see now that you meant disadvantage. I'd say it was a simple one: it's bright and stands out, much in the same way a gold/yellow emblem does only without a clever purpose. I'd say the same about gold/yellow boots or a cape. It stands out without a purpose when really there is no need, and various other in popular canon ways he can go.
As for what the non yellow emblem does for him, that's interesting. I'd argue it being black helps the blending in aspect obviously. As for it being in the shape of a bat at all, I would imagine that would have to do with his personal psychosis as presented in TDKT. He wants to reinforce the image and iconography of the traumatizing bat upon as many people as he can, he see's this as a war and he wants his banner(if you will) to have a shape that he carries around with him. If anything for easy reproduction.
It's why he lit the bridge on fire with his banner in the last film, similar to daredevil and the fire symbol on the road. It's why the bat symbol in the sky doesn't just read 'batman' but rather coveys his banner, it's why his ninja stars are in the shape of his banner. Flaunting around a specific banner for your enemies and allies has advantages found in the antiquity of war. Especially in the 'battle for a city'. Him wearing it around seemingly reinforces that. Not so different than carrying that Rome eagle into battle. People see it and they make the correlation directly to 'The Batman' and not other vigilante. Knowing you are facing the US army vs some other army...
There is also advantage is that stands for mean's something, see why caps shield looks the way it does and how that serves the premise in a way beyond the aesthetic, now that the bat stands for hope in nolan gotham that means such and such. Both points very much argued in stories such as DKR.
But that's my personal read.
As for seeing similar behavior in these boards, I can't speak for everyone. People tend to hate what they hate for whatever reasons, but to simply disregard what the man is stating in a direct reply to him, stood out to me.
I personally don't see how, when given an option, a ninja would seemingly grab the yellow tool bag, the yellow sword, yellow bandana...etc. Cause depending on the fiction, however grounded, it's all fake aesthics? I get why ninjas exposed various parts of their faces(including shredder) instead of going for the full(footclan 1990/cartoons) bags on their heads. But if they are creatures of stealth and shadows, it's pretty easy to see how some fans my appreciate things contributing to said premise vs against it.