The main benefit to the fiction is limited liability. Without delegating to the corporation the responsibility for corporate actions would need to be defined as

The main benefit to the fiction is limited liability. Without delegating to the corporation the responsibility for corporate actions would need to be defined as belonging to the owners, or all employees or some other structure where it all points to humans. If meta owes $18bn - I don't owe it - in the strong sense as a legal debt, as a shareholder in my 401k. The value of my ownership stake might go down (or up) but I don't have a shared legal obligation.