[evilduck]

Maybe a more tactful restatement:

This looks and feels a whole lot like what the Rails community was doing a decade ago with interpolated server-side values into ERB templates that contained script tags of jQuery. It seems like an old pattern that fell out of favor for good reasons (lack of fine grained control over the final rendered page's design and performance, still needing competencies in the front end tools when things don't work ideally, update and migration path difficulties for the front end, performance and caching issues, etc). I would personally not use Matestack as it seems like it has all the same pitfalls.