It is not just about Bitcoin, there has never been a time that it is good to brag about assets that you own.
As an investor, it is always good to keep everything you are doing to yourself and not reveal it to your friends or anyone, except people you trust very well.
You totally make sense but there's no reason what so why anyone will brag about having something or money because before he does someone else had it before him. Why the brag.
The topic reminds me of a friend that kills his best friend because he wanted to steal his Bitcoin holding so it, not security advice to publicly say I own Bitcoin either online or offline.
It's definitely not safe for a bitcoin holder to expose his bitcoin holding on the public because that will only result into making a crime. Just imagine how hard today to make a living and there you are, flaunting your expensive asset so expect that anyone will get interested on it and might think of making an action how to hack your own account. Things that are of high value should never be announced in the crowd. That is if you want to live safe and out from troubles. Think first its consequences before doing it.