Why the special secrecy?

I’ll see a post of someone celebrating the fact they’ve accumulated .1BTC, or .0001 BTC, or whatever, and inevitably someone chides them in the comments for sharing the fact they own X amount of BTC. I appreciate the wisdom of financial secrecy, and the fact that people are susceptible to theft up to and including by violence, but what makes BTC so (apparently) unique in this regard? Cash, cars, jewelry, every asset really, as well as banking passwords, IDs, SSNs, etc., are all open game given a proverbial gun to the head, and many such assets are openly flaunted anyway. Add to that the fact that BTC adoption (kinda, sorta?) depends on people sharing the fact of their own adoption. So what is so uniquely secret about owning BTC?