Sooo you believe that when our current system fails, you will still be able to sell and buy bitcoins? Like when our current currency is no longer usefull, sudd

Sooo you believe that when our current system fails, you will still be able to sell and buy bitcoins? Like when our current currency is no longer usefull, suddenly people will use bitcoins? How will anyone start to care about bitcoin if you can't really trade it for a currency normal people acutally use?