[css-pseudo] purpose of focus-within?

[jimmywarting]

Just discovered focus-within.
what dose it solve that :has() pseudo class can't fix?

eg:

form:has(:focus) { }
form:focus-within { }

I mostly think it's seems unnecessary to have focus-within, just adds more code, a yet another way of doing things

[Loirooriol]

:has is not in the dynamic profile because it's too expensive. This means you can only use it in querySelector or similar JS APIs, but not in CSS stylesheets. :focus-within can be used in both profiles.