You've mentioned no-code tools. For a client, I had to work with the no-code tool Bubble a lot. They do something similar, where the front-end is not built statically but dynamically and uses WebSockets to communicate with the back-end. I don't think this is a good idea (and that's why Bubble is also trying to switch to static pages now, but you can imagine what it takes to do that once you reach a certain size).
In fact the Pynecone frontend is built statically. But UI event handlers are run on the backend. The latency scenario is identical to if you used HTMX or Hotwire or a traditional web server. You click, it gets posted to the backend, an output comes back and is rendered.
The click counter thing is contrived and maybe Pynecone should have avoided centering on that, since the users they're targeting for sure don't care about frontend-only click counters.
