That is just the location of a page, and indeed that should be put in the URL. But a modern js app has much more state than that: partially filled fields, drafted documents, scroll position of lists, multi-path navigation history, widget display toggles, etc. etc. In react/vue you have 'stores' to hold and manipulate those info. In HTMX you need to choose between the url, the session cookie and the dom. And what you can usually keep just keep in the dom with client vue/react can't be with HTMX since the backend needs to be aware of the state to correctly render the new widget.