We’ve had this discussion elsewhere (several times, actually). I don’t seem to be able to find an easy link right now, annoyingly.
Using an API requires client-side JavaScript, which a significant proportion of users still don’t have enabled by default. That’s an instant cut off for a proportion of our audience, whereas rendering HTML server-side has no such drawback.
It’s still possible to change our tech stack, but not to client-side generation.