Design systems provide a different mindset for designers. The designer is forced to consider multiple constraints and scenarios instead of relying on a single design process. A design system is a set of principles, documentation, constraints, and patterns that enable different teams to create, maintain, and extend a design consistently and efficiently.
The various users of a design system are designers, developers, content creators, and product owners. A design system exists to overcome scale, inefficiency, and inconsistency. So if you've identified issues with inefficiency, inconsistency, and scale that can be improved through a mix of constraints, principles, patterns, and documentation, then you probably need a design system.
Design principles should be short and memorable markers of what the success of a design system should look like. There are many types of constraints that make up a design system, such as style guides, UX guidelines, and governance models. Patterns capture visual design patterns for reuse. Documentation is key to a successful design system, as multiple people in different roles must complete different tasks without having access to every form of expertise.