For me, the constant visual changes of new parts being streamed in are annoying, and straining on the eyes. Ideally, web frontends would honor `prefers-reduced-motion` and buffer the response when set.
Personally, I've fallen in love with that visual effect of streaming text you're talking about. It's a bit pavlovian, but I think in my head it signifies that I'm reading something high signal (even though it isn't always).