Earlier quoted context omitted.
"design systems" in recent frontend parlance is generally colors + fonts + screen wids + methodology + components (usually) that all fit a certain visual style/philosophy. Material Design can be considered a "design" system. While the pieces of design systems make sense in and of themselves (you can argue for a clearer, easier to read font), I think a lot of bullshit gets dragged in along with people wanting to embra…
Many of our products also support third party extensibility, so the main business reason we pitched internally was making this easier for external developers. This helped us convince the bosses to invest in the project and let us open source and maintain it. And hopefully with React Aria, we provide value beyond the standard "look at our fancy components".
Please feel free to amend/improve my definition of design systems above -- the term has meant so much over the years inside and out of the strict boundaries of pure graphic design -- I am not a designer/UX person by trade (I do it only when there is literally no one else), but write frontend code and have had some friends bellyache to me recently about trying to get design systems implemented in a local mid-large size company with a startup-like environment.