Pillar 1: Developer
Developers being a foundation pillar for Storybook, for them it's like playing with LEGO — One single brick can be added to many constructions.
Style guide defines the visual representation of a brand and establishes the root of its voice and tone.
It is more efficient and useful for developers considering parallel development with backend.

Pillar 2: Designer
As we agree with the above facts, the next question comes to our mind is, can Storybook help collaborating developers with designers?
It helps designers visualise the artifacts in real time with storybook preview to reduce expectation gaps if any.
The backing up quality supports access design guidelines, inclusive design, and redesign approach choices.
Further it comes with adaptive and shape-shifting components and patterns with firm guidelines and principles, that being utmost important for a designer.

Pillar 3: Client
Ultimately for the clients what matters is the end product. The major benefit for clients with the use of Storybook is:
Easy to visualise the enhancements or modifications with controls, components, data entry.
It makes clients’ life easy by providing support in testing edge cases before they are actually implemented in the website.
And the best use for clients comes into picture while they can verify UI accessibility and gauge performance through dashboards.