Twenty Twenty-Four as a reference, not a parent

The 6.4 default theme is the clearest worked example of a pattern-driven block theme, and using it as a parent is a different decision entirely.

what it is good for:
  reading theme.json v2 written well
  seeing patterns used as the primary building block
  the section-style approach to colour

what child-theming it costs:
  every core update changes your parent
  the patterns are theirs, named in their namespace
  a design that is recognisably the default theme

we copied the theme.json structure and wrote our own.

Reading a default theme as a reference is undervalued and child-theming one is usually a mistake for client work — the parent changes on WordPress’s schedule rather than the project’s, and the resemblance is visible to anybody who has seen the default. What transferred was the structure: patterns as the unit of composition, and section styles rather than per-block overrides.