Here's that plan laid out: Sell BTC for EUR; deposit EUR in a checking
account/savings account; receive a bank's interest on the EUR. As
customers demand the BTC in the amounts enumerated in BTC that you
still owe them (in great numbers after some announcement like the
above, or otherwise), buy BTC with EUR and sell it to the customers.
Pray continuously that you don't lose your shirt with these
conversions, particularly given that unexpected spikes in BTC demand
will come precisely at those times that you'll tend to lose out on a
conversion.
You might, extremely conservatively, sell BTC to people in exchange
for a promise of a greater amount of future BTC (i.e., you might lend
BTC out). Step 1 in that scheme: find anyone who will borrow BTC who
isn't either a lunatic (and therefore unlikely to be able to repay the
loan) or a thief. After subtracting lunatics and thieves, you're left
with people who will take some BTC, sell it for EUR, attempt to make
money, and then at a future date buy BTC for with any EUR they've
made. I.e., with people who will need to pray almost as hard and as
long and with as much chicken blood and magic circles as an exchange
that took your suggestion to get interest from a bank. Your
borrowers won't have to fear a sudden demand for the money, but
they'll still have to fear the BTC:EUR exchange rate.
Meanwhile, approximately 100% of BTC holders are speculating in the currency.
You might, extremely conservatively, sell BTC to people in exchange for a promise of a greater amount of future BTC (i.e., you might lend BTC out). Step 1 in that scheme: find anyone who will borrow BTC who isn't either a lunatic (and therefore unlikely to be able to repay the loan) or a thief. After subtracting lunatics and thieves, you're left with people who will take some BTC, sell it for EUR, attempt to make money, and then at a future date buy BTC for with any EUR they've made. I.e., with people who will need to pray almost as hard and as long and with as much chicken blood and magic circles as an exchange that took your suggestion to get interest from a bank. Your borrowers won't have to fear a sudden demand for the money, but they'll still have to fear the BTC:EUR exchange rate.
Meanwhile, approximately 100% of BTC holders are speculating in the currency.