I think an important caveat here is that in a serverside-rendered context, linaria’s 70kb of CSS would be a bigger issue than styled-component’s additional JS.

I think an important caveat here is that in a serverside-rendered context, linaria’s 70kb of CSS would be a bigger issue than styled-component’s additional JS. The page can’t render until it has downloaded the CSS. Granted, many react apps aren’t serverside-rendered, so these numbers are still useful and interesting. But I would say that if performance is a priority, moving to an SSR solution (or away from React altogether) would have a way bigger impact on performance.