It’s certainly fragile yeah. There’s 16.7m bit coins about and the strength of a current is usually based on who uses it and what for.
As an example, the US Dollar’s strength comes from the US manufacturing industry and US economy allied to the fact that the dollar is used to trade oil and gas. The last two leaders of oil and gas producing countries that suggested using other currencies were Ghadaffi and Saddem and you won’t need reminding how things turned out fo then.
BitCoin is not really used to purchase goods at present and it’s strength is entirely sentiment led. As soon as people stop believing in it then everyone will notice that the Emperor is stark bollock naked.