Like many powerful currencies in the past, USD may fall to ground too, my question is will that effect BTC value? Or is it independent of all other real world or non digital currencies of the world?
We could see that already more people are switching from USD to bitcoins.If USD falls,then more people would leave USD and start buying bitcoins.It would increase the demand for bitcoins and bitcoin price would go more higher.If such situation continues,then more countries would start to accept bitcoins as medium of exchange instead of USD.
No one is "switching" from USD to bitcoins, they are buying bitcoins on the belief the value will go up but they aren't actually transacting in bitcoins. At least this is true for the vast majority of people.