Depends on the company. Some design systems are comprehensive, mature, and general enough that they're suitable for use by hobbyist devs or smaller orgs that w

Depends on the company. Some design systems are comprehensive, mature, and general enough that they're suitable for use by hobbyist devs or smaller orgs that want attractive, versatile UI components but don't want to spend effort spinning up something of comparable quality internally. Ant design comes to mind as one I see frequently. The other benefit is companies that offer extensive third party integrations, like saleforce with their Lightning design system. By making the DS available, they let third parties build plugins that feel like a part of the platform, with high quality tools. This helps negate a lot of common problems with platform plugins that are ugly/unintuitive/broken. Design system tooling (as opposed to UI component libraries) is more of a traditional open source / giving back dynamic. Theo from Salesforce and Style Dict from Amazon are widely used as part of the infrastructure underlying smaller companies' internal design system efforts, without going so far as to influence specific component implementations or visual styles. It's akin to FB and google opensourcing data infrastructure tooling.