Blocks storing data in post meta don’t need save functions since the data already exists in the database. Instead, they require dynamic rendering to display meta values on the frontend.
Static blocks with save functions store HTML in post content, but this creates stale data problems for dynamic content like recent posts lists that change independently of block edits.
Dynamic blocks save only placeholders to the database while using PHP render callbacks to generate fresh content on each page load, solving both meta display and dynamic content challenges.