Aren’t other nodes the third parties?
If you are talking automated loan, you should look into credit lines backed by assets. Pledge assets lines. Once open, it’s fully automated and you don’t need to interact with a third party either.
In honesty I have no experience with a pledge asset line but I can guarantee you that if the institutions involved in conducting it wanted to, they could cancel it on you anytime. With a correctly coded smart contract on Ethereum, you could ensure that never happens.
One system requires trust in third parties. One gives you the option to design a system to minimise or eliminate it.
Please note that the lack of paperwork in Ethereum just means you borrow or loan money in a way that might be not legal. I am all for removing redtape here.