What is the purpose of contracts?

Contracts are not just a legal document enforceable by law. Contracts are made for:

Successful business outcome for contracting parties
Relationship-building
Effective information (user-friendly for clients, contracting parties, & non-legal audience)
Making sure that essential terms are dealt with thoughtfully (Limitation of Liability, Indemnities, Governing Law, Termination, or Insurance)
Legal risk management
Compliance
Sales and Marketing leverage