Fiat has policies which promote store of value which, I believe, crypto currencies could learn from. There are safeguards in place to automatically shut down stock market trading if markets fall too much(something bitcoin might benefit from). Capital gains taxes promote HODL and long term holding strategies in equities markets by rewarding HODL trading over short term daytrading.
I'm not sure if you live in the US, where the tax rules are pretty much what you describe above. The federal tax authority (IRS) treats cryptos as 'property' for tax purposes, so you pay normal capital gains taxes, which are lower for coins held for one year or longer.
In the West, I think circuit breakers still carry the stigma of elite control and dysfunctional markets. Even though everybody eventually uses them, the Western authorities still try to appear they have a lighter touch than others. (The Western media were laughing at the Shanghai stock market recently for its way of using circuit breakers.)
The same applies to cryptos -- although I tend to think, since we're stepping into a new monetary era of adjustable de facto gold-silver-crypto standards, all markets for non-state monetary assets are heavily manipulated by the elites anyway. So circuit breakers would just mean a slightly different approach to price control.