I'm extremely cautious about complexity, yet have adopted a claude-based dev flow. It comes down to watching and guiding it, and not letting it run autonomously. At a certain point your codebase will tip over into the patterns you've defined and claude will recognize and follow them. Just treat Claude as a vim editor mode and you will see a big difference, and your relationship to the tool will change.
Happy to see a new CSS-in-JS lib. All of this madness about runtime performance costs does not apply to 99.9% of the population. But good abstractions do. And then there's latency, and machines are getting faster, and browsers getting better, etc etc. This whole argument and the related FUD was all a non-issue to begin with, at the great cost to DX.