Use something else if you prefer, gold or you could even sit atop bitcoin if parties find that more agreeable to transact in.

If I say I owe bitcoin, that's a transaction where I cash into bitcoin and then resolve my debt via bitcoin, but do I want my debt in bitcoin, maybe, but the value does vary more than USD.

A credit agency might not care if you improve your credit (by paying or resolving debts) in bitcoin, or may also give the option of cash or some other cheaper transaction form.