I'd perhaps generalize that to "it's useful to have visual grouping correlate with semantic grouping"; applies to separating words with spaces, sentences with punctuation, paragraphs with newlines, lines of code, UIs, and much more.

An important question for this also is what qualifies for "single thing"; you can look at a "for (int i = 0; i < n; i++) sum += arr[i]" as like 5 or more things (separate parts), 2 things (loop, body), or just one thing ("sum"). What array languages enable is squeezing quite a bit into the space of "single thing" (though I personally don't go as far as the popular k examples of ultra-terseness).