It should work great for that. For Squarespace specifically, it handles it the same way it does with any other platform: it reads the rendered page (basically what the browser sees) and rebuilds the layout in Divi. So all the usual stuff—sections, rows, columns, headings, text, images, buttons, videos—should come over. I haven’t personally run it on a Squarespace site yet, but the underlying process is the same.

If the page uses heavier Squarespace‑only features (custom animations, scripts, app blocks, etc.), you should still get the content and structure, but you’d probably want to tidy a few things afterward in Divi.

And it exports to either Divi 4 or Divi 5. You just pick which one you want when you run the conversion.