What happens to BTC if the protocol succeeds but the currency fails?

[jsteelbeam]

I'm new to Bitcoin and after doing alot of reading and research I came up with a question that has to deal with the long-term use of BTC.

It is my understanding that bitcoin is the protocol for a decentralized public ledger and Bitcoins are the vehicle to transfer money on that protocol as an application.  So utilizing the Bitcoins application you have currency, money transfer, remittences, etc.

It is also my understanding that the bitcoin protocol can also host other applications called distributed contacts for escrow, smart properties, lotteries, etc.

I have heard it said (and I agree), that Bitcoin the currency can fail while bitcoin the protocol can succeed.  The question I have is what happens to the Bitcoins that we are "buying" today if the currency fails?  Are they somehow required to be used in the distributed contracts applications or do they become "worthless"?