I feel like Bitcoin opened people's eyes to this. I understand that the dollar is at a vulnerable time, but this has not been the first time in history that the dollar has been unable and no longer a safe haven. Now, people have seen that there can be an alternative to this, instead of continuing to hope that the traditional one will fail.
It may not be the sole reason, but Bitcoin plays a role in this. People are now looking for alternatives to traditional investments and currencies, something that people didn't really think about before, not like they were not there before, but like you said, people preferred a safe haven.
I disagree though, I think US dollar is still a safe haven that's why there are a lot of countries still holding it. Of course there is the old and traditional Gold for every nation as it has been proven to be a safe haven specially after the world war that's why governments around the world is accumulating it.
Although I will have to agree that at some point in history, perhaps Bitcoin could be another alternatives. For now we have seen it to be that case, as US once have talk about it being as a reserves and so other nations too might have been swayed by it. But the first step is that the nations should readily accept and not ban it and really have to do some experiments or at least understand the very basics of Bitcoin, i.e. speculative asset, mining, bear/bull cycle etc.