Unless the volatility were to go down in the extreme, nobody has any business borrowing or lending in bitcoin. I'm sorry but it's absurd, unless done as speculation.
Basically, borrow bitcoin and you are in a short BTC speculative trade, lend it and you are long the same. If you'd borrowed $100 worth of bitcoin last year, you'd owe what, $1,000 this year? It's not a loan, it's a bet. And how do futures fix this?
Rates? Even mentioning rates on a BTC "loan" sounds entirely out of place.
OK but money isn't just about credit. It has two other functions: store of value and means of exchange.
As a store of value BTC is highly uncertain. It will multiply or decimate whatever value you try to store in it.
I thought it might be interesting as a means of exchange, and maybe it is in certain situations, but commissions seem too high for use as a major global digital payment system. You pay out of your currency to BTC, then from BTC to the target currency, plus the transaction fees which can be prohibitive unless you're moving some serious loot. I make a lot of small international payments and would love a great solution, but I can't see bitcoin as it. Who actually uses BTC? I mean, other than speculators? ("Investor" is a euphemism here, buyers of bitcoin are commodity or currency speculators.)