Of course they aren't, just a little thought experiment.
How different do you think things might be? Better or worse?
Maybe financial exploitation might be a thing. (Instead of feet) people assume selling bb pics is the easiest money.
There'd be so many more fakers wanting to sell their OF.
But ton the upside, we might get to see more rare and weird buttons? A lot more porn, both good and bad
You ever notice anyone checking out your belly button in public?
Do you even show your belly button or not?
I'm here with the answer to the question that nobody asked (but should have): How does one properly photograph a belly button?
A simple guide for phones:
1. Use pro/RAW mode
This is possibly the most important step, you want details!
Your individual phone may vary, but most will apply some kind of filtering/smoothing filtering (sometimes even when disabled in the menu settings). Pro or RAW modes will often disable it fully. If you don't have this option, disable as much smoothing or filtering as you can anyway.
2. Lighting
Never use flashes*
Bright, natural light is good. Diffused natural light is best (think a bright indoor room). Direct light is always bad.
*unless you're in such a dark environment, and there's no choice
3. Open it up!
We want to see the actual button. Use spare hand(s) to spread open the hole, the slit, or lift the hood, whatever. Photos facing the button directly are great.
4. Trim hairs
This really shouldn't be controversial. Yes, most people will have visible hair when you're taking closeups. But sometimes (especially in my case), some stray hairs will actually cover my button. It only takes a minute to shave around the hole so no hairs get in the way.
5. Distance
As close as possible while maintaining sharp focus. Too close, and your phone might not focus correctly. Too far, and it won't get a clear pic. Bathroom mirror selfies are good for body shots, terrible for navel pics.
Bonus:
It should go without saying, use the primary camera. Never use the selfie (front facing) camera.
If you want the best possible pics from a phone, you could also get a simple clip-on macro lens. But most flagship phones nowadays should get good enough results using these steps.
Semi-pro guide I'll keep this quick, because pros should know what they're doing (but I've often seen these mistakes - studios could still find this helpful).
Lighting - Main light above subject. Again, no direct light or ring flashes. Fill light to create shape, shadow and depth. Natural, bounce or softbox are all good.
Aperture - If you need to, bias for smaller aperture and more brightness. This increases depth of field and greatly decreases any autofocus issues.
Do you prefer male or female ones?
Edit: This is not a honeypot to draw out female members lol, I'm genuinely curious. I have this suspicion that women might like female (or 'feminine presenting' male) buttons at least equally and perhaps more so than male buttons. But idk
Does a person's face or body influence how much you enjoy their belly button?
Don't get me wrong, I love a good button for its inherent beauty. And in fact, I've seen some people (I found not particularly attractive) become much more so if their button is really pretty.
But I think it still affects me.
Take a similar belly button on two people, one random or one with a face/body I really like. I'll enjoy the latter more.