Looking at the comments from the dev in this thread it seems this really only supports vertically stacked layouts right now? At least the demos were responsive but each component seems to assume that it fills the width of the screen. Making responsive components in a columnar layout might be more challenging for this kind of toolset to handle.
Looking at the recipe for next.js app I noticed that the component where the page is rendered appears to be in `[...puckPath]/client.tsx` which is a "use client" component. That makes me wonder about the entire framework and whether or not it actually renders the pages on the client or the server.
If those two things are true then this might have limited application. Finding a way to handle responsive layout for columnar and/or grid based pages will be non-trivial. Finding how to mix server and client components effectively will be non-trivial.
That aside, it seems useful and decently structured. In places where we I've worked where there is a lot of customization desired, having a UI builder that customizes page layout in some data format (json or xml) has been very helpful.