Yea the trouble is that you will have to hand over Bitcoin to whomever you borrow the FIAT
from, this means you lose control of that Bitcoin and when the value falls you will have to
give them more Bitcoin to cover the value of the FIAT loan, its like a "Margin Call".
Why would you have to hand over your Bitcoin? Perhaps you do now, but I am talking about the future when Bitcoin is more established. You don’t have to move out of your house when you use it as collateral. You only have to prove that you possess the asset that you’re using.