CSV files are MUCH easier to search and inspect using tools like grep and less. It's the accounting people that want's Excel, but as a developer CSV is easier and more flexible.
We process csv files containing payment information, export csv as product feeds for perhaps 10 different partners. It works, it's faster than XML or JSON and is easy for non-technical people to inspect using tools like Excel. Most cvs data exports are not something that's made up on the fly every day, it batch jobs that create the same type of CSV file each and every time.
CSV is alright. XML is bullshit.