CSV can be manually read/edited by non-technical/non-developer humans using commonly available tools like Excel and Notepad. Not many of the better data formats match that criteria.
Notepad, I agree. Excel... not so much: it tends to change data silently unless you are very cautious with your environment (e.g. dates transformed to number of days since 1900, and some strings to dates)
That helps, no doubt. But last week one of my coworkers touched a Csv with Excel, and all dates went from ISO8601 to MDY. We are based in Europe (i.e. we use DMY at minimum). In my experience, a Csv touched by Excel is not trustable for further analysis.
