Here are the most important advantages of a Wordpress Multisite in comparison to a standalone Installation

Central Administration

• Manage multiple websites from a single dashboard
• One-time updates for WordPress core, themes, and plugins apply to all sites
• Centralized user management across all sites

Cost & Resource Efficiency

• Only one hosting package needed for multiple sites
• Shared database and file system reduces storage overhead
• One SSL certificate can cover all subsites (wildcard SSL)

Consistency

• Themes and plugins are installed once and can be shared across all sites
• Uniform design and branding is easier to maintain
• Standardized functionality across all sites

Scalability

• New sites can be added quickly without a full WordPress installation
• Ideal for agencies, networks, or companies managing many websites

Disadvantages to consider:

• If the main installation has a problem, all sites are affected
• Plugin/theme conflicts can impact all sites
• Less flexibility for individual sites compared to standalone installations
• Can be more complex to set up and manage for beginners

In summary, a Multisite is ideal when you need to manage multiple similar websites centrally, while a standalone installation is better suited for a single, independent website that requires maximum flexibility.