It's specifically built for Rails, so yeah, it definitely assumes full-stack control.
And there are definitely applications I would prefer to write as an SPA over the Hotwire approach. But given that the vast majority of websites are just a series of simple forms, I prefer this approach over the costs you incur from building an entire complex SPA.
And there are definitely applications I would prefer to write as an SPA over the Hotwire approach. But given that the vast majority of websites are just a series of simple forms, I prefer this approach over the costs you incur from building an entire complex SPA.