That sounds like use-case exploration? Did you answer?
It sounds like they are referring to hx-swap and not arbitrary javascript callbacks though, and in that case, I don't see why calling JSON.parse() inside htmx (when the content-type is json) is that big of a deal.
1. make an MPA 2. each page is a resource 3. keep a stream open on the current state of that resource 4. ship, touch grass, repeat
Uh, yes? They wrote a literal book about why they think this is important: https://hypermedia.systems/