They will show the bitcoin as collateral (asset), and lend money up to 10x value of that bitcoin. (horribly insane fractional reserve lending allowance in us law).

or, they can create an 'asset' (hedge fund) by indexing it on bitcoin, then start trading and inflating the hedge fund's value, and then show both bitcoin and the hedge fund as assets (duplicate !!!!) and then lend 10x value of those totals as money.

by the way, that last bit was how the financial scam was pulled in wall street - that lead up to the 2008 crash.