> Why have HTML elements react to changes in data or state, rather than just insert new HTML elements already updated with the new state? But what's the big di

> Why have HTML elements react to changes in data or state, rather than just insert new HTML elements already updated with the new state? But what's the big difference? Something somewhere must react to change. Either modify the DOM by client-side code, or modify/replace it by loading content-fragments from the server. I would (perhaps naively) think that doing more on the client is faster than both re-rendering on the server and reloading from the server. Maybe it's just that React is too big and complicated and therefore slow.