Money in the form of coin, currency or emoney is a medium of exchange and store of value.
Debt, although denominated in amounts of currency units, is a contractual obligation to pay money at a future date. It's a legal contract enforceable at law using the machinery of the state.
For example, if a bitcoin holder lends you bitcoin to buy a house, the mortgage is still a contract between you and the bitcoin lender. The mortgage has nothing to do with the bitcoin system. It is still registered by the government, and the sheriff still comes to evict you if you don't pay up.
Debt, although denominated in amounts of currency units, is a contractual obligation to pay money at a future date. It's a legal contract enforceable at law using the machinery of the state.
For example, if a bitcoin holder lends you bitcoin to buy a house, the mortgage is still a contract between you and the bitcoin lender. The mortgage has nothing to do with the bitcoin system. It is still registered by the government, and the sheriff still comes to evict you if you don't pay up.