Because I know how precise they need to be. My main experience is time aligning with monitor mixes from different recorders. So it's generally a pretty clear soundboard-type pull. So any sort of issues with the time alignment and you start getting phasing VERY fast. However, the mixes are sometimes wildly different, so you need to use your common sense to figure out if a sync point is truly a sync point, and not just a similar looking wave form.
See the attached picture. Here's a time alignment that my friend did and I looked over. The dotted lines are the sync markers that he put in, because it looked like that was the start of the snare hit. However, if you look at the whole wave form, at least in that 1/50th of a second view, you'll see the dotted lines don't work. Instead, the correct sync point would be something like where the cursor is, and a majority of the peaks/valleys line up.
I don't really trust an automated program to not get tripped up on minor instances like that, and would end up checking every sync point before processing. That said--if it has some other functionality like ability to move/recalibrate sync points, it could be useful.