bitcoin is/will be the best collateral - i'm guessing that in the future they will pay a very nice premium to use it as collateral. The trick would be lending to the bank while also holding your keys so that you couldn't get rug-pulled. 

But looking further into the thread I also started thinking that banks might be paying premium to have better collateral available for their business in the times of instability. But this is deeply confusing and seems that LN key rate idea is pretty self sufficient and adequate. 