The library in the post itself is pretty new, so I don't think there are any real examples out there aside from the website advertising it.
That said, its idea of sending HTML from the backend and showing it in the frontend isn't new - HTMX has been pretty popular the past few years and is basically the same thing. It's great for any type of website that doesn't update often, so anything that isn't a webapp or does a lot of things from the client side. There's a popular article of a company switching from React to HTMX which simplified the code heavily.
Oooh yeah, I actually considered the SP at first but it wasn't in stock where I live. That might've been a good thing though, because the H is very comfortable to hold whereas clamshells generally aren't. But yeah, it's really hard to justify buying more than one of these.