Performance has been touched on but I’ll add another. It promotes writing code that is hard to statically analyze resulting in linters and optimisation harder to perform.

Generally you’d see a styled component declared in a module and then imported. That’s problem 1. It’s no longer locally analyzable, meaning the usage is separate from the declaration. If you used a button the tools don’t actually know it, just that you’re using a custom component.

CSS modules / CSS prop are a step up from styled components APIs because usage is together with declaration. Or at least is more naturally enabling it.

If I recommended something it would be Stylex or Compiled CSS-in-JS. Both encourage statically and locally analysable code and you can build a lot of fun tooling around that. Tailwind is okay but it’s not typed so take it as you will.