New SharePoint List Forms can't embed outside SharePoint

Hi all, SharePoint lists have a new "Forms" tool. These create a form in the style of Microsoft Forms for users to submit new entries to the SharePoint List. This is great: Microsoft Forms provide a much nicer submission experience than the form with the old "new" button, and this removes the need to maintain a Power Automate flow to move form responses to a list. You'll find it via the "Forms" button at the top of any list in Microsoft Lists.

However I've noticed one critical difference from "vanilla" Microsoft Forms. I'm able to embed a vanilla Microsoft Form on any webpage, on any domain. I tested on Codepen.io, something like this:

<iframe width="640px" height="480px" src="https://forms.microsoft.com/Pages/ResponsePage.aspx?id={{FORM_ID}}&embed=true" </iframe>

But these new forms "powered by Microsoft Lists" don't let me embed on other sites. I can embed the form on a page on the same SharePoint site, but not on external domains.

<iframe width="640px" height="480px" src="https://{{DOMAIN}}.sharepoint.com/:l:/s/{{SHAREPOINT_SITE}}/{{FORM_ID}}&embed=true" </iframe>

I get a crossed out, red circle with "{{DOMAIN}}.sharepoint.com refused to connect" under it when I test on Codepen.io or elsewhere.

Is this intentional? Is there any work around? I lose a lot of value if I can't embed this form in other domains, but also would hate to make a vanilla Microsoft Form and have to manage a Power Automate flow to ensure items are added to the list.