With 100% reserve bank, there would be no interest to earn. Because it would be a true bank, more likely you would pay fees for storing your bitcoins there. The benefit is that the bitcoins itself would no lose value, and would always appreciate in long run, thus keeping your savings safe.
What about loans? The point of FRB is that it can be used to lend money to individuals or businesses. Is bitcoin not suitable for lending?
Ok, you don't need FRB to lend money, but it surely increases the amount that you can lend and therefore decreases the cost of lending. Otherwise lending will get much more expensive. Will it not?
As for bank runs, they are a problem with the current banking system too. That's why Cyprus shut the banks for several days. If there is a bank run with FRB, people may lose their deposits, no matter if they were in euros or bitcoins.
Is there going to be a cryptoloaning technology invented that does not require banks? I suppose this would be something like crowdfunding, but safer in terms of tracking where your loan goes and possibly getting part of it back, if necessary.