The difference is that FAST is NOT a component library. It is a tool for building component libraries. The fast-components package is a showcase of what this li

The difference is that FAST is NOT a component library. It is a tool for building component libraries. The fast-components package is a showcase of what this library is capable of. You could use FAST to create web component libraries that consume bootstrap styles if you want. Microsoft is using this same base to write web components for Fluent UI (previously Office Fabric): https://www.npmjs.com/package/@fluentui/web-components https://www.npmjs.com/package/@fluentui/web-components