The primary reason to sort reputation changes by time is to understand the chronology of events. But this purpose is largely defeated by the fact that only the last event is shown for every post:
The events are chronologically sorted -- except they are not, because those six upvotes did not all come at 12:38, and other five did not come at 23:17. The only way to see the full timeline of events is to switch to grouping by posts, and expand all of them. And then, of course, the timeline is permuted:
It seems the only way to reconstruct the sequence of events of a day is to choose the latter view and re-sort by time in a spreadsheet or something. I think this is suboptimal.