<i>An example may be useful. Suppose I tell you that I have written an Ethereum contract whereby people can loan me money, and after a year, I will pay them back double. Before you enter into one such contract with me, I hope it would cross your mind to wonder if I might actually be running a Ponzi scheme. Don&#x27;t worry, I say, Ethereum has this gas feature that means the transaction will always halt. How much more confident should that information make you feel?</i><p>Again, it has nothing to do with gas.
You just need to review&#x2F;audit the contract&#x27;s source and EVM code and be sure it doesn&#x27;t have backdoors.<p>For simplicity, you can think about Ethereum Transaction as an RPC call to Ethereum contract, where in addition to arguments (Data), you can also transfer a monetary value (in Ether) and provide fuel (Gas) for contract execution. Gas price (in Ethers) serves the same function as Bitcoin Tx fee.<p>Gas mechanism is just an implementation detail.<p>EDIT:<p>Regarding the contract example you mentioned &quot;unsecured loan&quot;, I&#x27;m not sure it can be implemented as a &quot;Self-enforcing contract&quot;, which is a proper term for &quot;Smart Contracts&quot;. If a contract depends on your will or ability of repaying the loan, then it&#x27;s not a self-enforcing contract. Somebody need to provide a collateral. It doesn&#x27;t make sense for you to put up a 1001 Ether collateral to take 1000 Ether loan.<p>With smart property represented on the Blockchain you will be able to put up your car or apartment as a collateral for a loan, then it can be made self-enforceable. But it&#x27;s not there yet.<p>The only way I can see for it to be implemented is with your own token, which will be devaluated each time somebody not repaying the loan in full.