For a non developer like me, Is it any different from Ant Design (https://ant.design/ https://ant.design/)? Also, almost every company I worked with (> 500 em

For a non developer like me, Is it any different from Ant Design (https://ant.design/ https://ant.design/)? Also, almost every company I worked with (> 500 employees), eventually built their own UI components. And in every company, developers seldom use these, always customize or use something else. Which brings the question - Why do we invest (internally) and open source components? Whats the value?