Hearn simply does not understand bitcoin.

He thinks it is suppose to be Paypal with super fast transactions.  There are already technologies to do fast transactions, not sure why someone would want
to change bitcoin to do that and more importantly why?  You don't need bitcoin to do fast transactions.  Ask Visa.  They did it and are very successful at it.

If you want a public ledger, irreversible transactions, cryptographically secured by best, distributed network (self supported), you might look at bitcoin.

I doubt R3 will have the brain power to pull this one off.  I think their first mistake was to hire Hearn.

Network effect will eat them live. What will happen, they will burn investors money and say, well, it was a good experiment.  
But if they get 40 banks to collaborate, who knows.  They might build their private blockchain to run it among themselves for inter-bank transactions but I'm
not sure where the hashrate will come from to secure it.  Who is going to pay for it?

I know one thing, banks are the worst places to work on innovative projects.  They are users of technology, they don't create anything new.