Most design system business cases lean on consistency: fewer inconsistent buttons, a tidier brand, happier design leads. It's a reasonable argument, but it's rarely the one that gets budget approved at enterprise scale.
The argument that does get approved is velocity. When we audited component reuse across a recent banking engagement, we found product teams were rebuilding the same form patterns an average of six times a year across different squads — each rebuild carrying its own accessibility gaps and QA cycles.
A shared design system doesn't just standardise appearance. It compresses the distance between a validated pattern and a shipped feature. In organisations running ten or more product teams, that compression is worth measuring in engineering hours, not brand guidelines.
The teams that get the most from a design system treat it as a product with its own roadmap, owner and adoption metrics — not a Figma file handed down once and left to decay.