In reply to Nobody.

To expand on that, Bitcoin is secured by people willing to run Bitcoin mining computers that add the new transactions to the ledger. They solve math problems sort of like a lottery. The system is secured because a bad actor would have to solve the math problems faster then everyone else combined. Without the "block rewards" and transaction fees the miners have no incentive to run those computers and secure the system.

I am running one now that is not profitable to operate except it is heating my spare bedroom so it replaced a heater.