Structured Data is machine-readable markup added to pages to help search engines understand entities, content types, and relationships.
It matters because technical issues can prevent great content from being discovered, rendered, indexed, or trusted. Strong technical foundations protect rankings during redesigns, migrations, content expansion, and platform changes.
Example
A business can provide machine-readable organization details alongside its visible contact information. Validate the structured data and keep the names and URLs consistent with the page, rather than adding unsupported claims solely for search engines.