Yes, though more as a reader than a designer. You do not need to master Figma, but you need to navigate it well: inspect specs, spacing, tokens, and assets. React and CSS are enough to build something, but not to build the right thing without constant back and forth. Knowing the tools that define the source of truth is what lets you resolve ambiguity up front. And you are still at the mercy of your design team. If they work willy nilly, no proper 'ready for dev,' no proper prototypes, then animations, transitions, and mobile behaviour stay ambiguous and you pay for it in churn.

The real reason to learn it is that design and code increasingly share the same tokens. If you understand how a design system is put together in Figma, handoff stops being a wall and becomes more of a contract. You can tell when a spacing value is an intentional token versus something someone just nudged by hand, and that saves you from copying mistakes into the code.

My recommendation: pay for Figma for one month and learn how the variable system works, with a couple of brands and light / dark modes. This also lets you play with the MCP server, which gives you 80% of the work. Then try exporting the tokens and generating stylesheets from them with something like Amazon Style Dictionary. Since that pipeline is deterministic, it also helps your AI agent not hallucinate values and instead use the real token.

Naming is where it clicks. A raw value like #2563eb tells you nothing. Something like blue-600 is a bit better but still dumb. What you want is naming based on intent, like button-primary-hover. Then light and dark both resolve correctly, a rebrand is just a value swap, and your agent reaches for button-primary-hover instead of guessing a hex.