Because unless you have a one world government (hopefully, no one is a proponent of this), there will be at least some countries that will welcome you. And since the rewards will be large enough, market participants will even do illegal things to access it.
All it will eventually do is make your country less competitive until you have no recourse but to change the law. FOMO isn't just for people; it's for nations as well.
The rewards are minuscule. It's a niche industry with no potential of it ever not being niche unless is has mass adoption.
Bitcoin has a very, very short history of being a decent store of value and the US Government publicly saying they plan to break it would collapse the entire scheme.
Not sure that is true
> According to security firm Sophos, 51% of organizations it sampled globally found themselves the targets of ransomware attacks in 2019. The crooks succeeded in encrypting data in 73% of these attacks. Just over a quarter of these organizations paid the ransom, or their insurance companies forked over the cash.
https://m-cacm.acm.org/magazines/2021/4/251337-the-worsening...
They can harden their stance all they want, but breaking the crypto ecosystem is incredibly easy if governments really wanted to. All you have to do is ban companies from interacting with crypto currencies in any form, be it accepting, exchanging, holding, or producing them. That would immediately shut off the gateways between the crypto ecosystem and the real economy, which reduces crypto to P2P transactions in parking lots.