Treating design files like code means working in branches. A branch keeps the main system stable while exploration happens. Changes get reviewed before they affect the shared source, and work can happen in parallel without corrupting what the team relies on. This is the operational version of [[Software design should be opinionated]] applied to file management: the opinion is that the source should be protected from work in progress.
Skipping branches under time pressure is where [[Design debt as a performance indicator]] accumulates. The cost of inconsistency in a shared design system is high, and [[Implementing a design system]] depends on this discipline being in place before adoption can happen, because teams won’t trust a system they’ve seen get corrupted.