Possibly many LiveView tech demos / projects by the community haven't had much thought into latency, but LiveView itself even contains a latency simulator[0] built-in. Additionally, it can toggle classes on elements when you click them and turn them off again when an acknowledgment has been received from the backend [1]. Finally you have the JS hooks, through which you can just implement any kind of loading indication you want on the frontend. So the tools are there, they just need to be used.

[0] https://hexdocs.pm/phoenix_live_view/js-interop.html#simulat...

[1] https://hexdocs.pm/phoenix_live_view/js-interop.html#loading...