It is not really a protection.
Basically, these companies file under Chapter 11 of the U.S. Bankruptcy Code, which is called debt reorganization.
In this case, companies are allowed to continue businesses as usual. At the same time, suppliers can't stop their goods and service to the companies because the companies is in process of reorganizing debt, but not fully liquidate or close down.
The best thing is the companies may be survive and regain from such "protection". Also, debtors may be able to recover more. A famous example is United Airlines, which they did not stop their service during reorganization.
The companies subject to Chapter 11 will have the absolute advantage because they are fully protected. Employees can't stop working because they are reorganizing debt.
If they choose not to file with Chapter 11, then it will be Chapter 7 - Liquidation.