Line-by-line streaming: who approved this and why?

The latest version introduced line-by-line text streaming. I assume whoever designed this was inspired by watching a dot-matrix printer from 1987, because the effect is identical: text crawls onto the screen line by line, the layout constantly shifts, and reading anything mid-response is simply not possible.

I genuinely cannot fathom what user problem this was meant to solve. The previous behavior — rendering text as it arrived, without turning the output area into a slot machine — worked perfectly well. This is a step backwards in usability presented as a feature.

Please provide an option to disable it. Or, alternatively, explain the reasoning — I'm open to being wrong, but right now this looks like a change made by someone who has never had to actually read their own tool's output.