The expression "I need this yesterday" is literally possible with a shelf company.  Some jurisdictions take a few days to weeks to register a new company and shelf companies can save critical time in these cases.

Additionally, companies which have a bit of longevity often find it easier to obtain credit, bid for contracts and conduct international business since many entities are wary about engaging in business with companies having a short business history.  Therefore, an aged shelf company or "vintage company" can often provide a solution to this problem.