Amazing python to website framework. It is just what I was looking for!
Is it intentionally slowed down? The reaction (for example when I click the checkbox) seem very slow in the demo page.
This is probably the main drawback; you need your server to be located physically close to where the UI is open or there will be a very noticable delay. It's probably pretty snappy when the server and browser are on the same machine, though.
I’ve tended to use this in UIs which rely on server state, and it usually makes things feel much snappier. In my experience it’s rare that an optimistic update isn’t fulfilled as expected, so the user experience is improved overall.
I’d hesitate to do it absolutely everywhere, though. In large forms it would be preferable to do batch updates rather than updating on every field interaction, for example.
There are pitfalls (what if the user thinks a setting saved and closes their browser, but it failed after they closed the tab?) which are addressable but it takes work and complexity. I think optimistic UI can be helpful. Generally speaking it’s a layer of complexity I’d tend to try to avoid, though.
Tools like Relay for graphql come with excellent implementations of this which I’d say are worth using if you’ve adopted the library, for example.