The advantage you mentioned is the one I've seen that has the most benefit. If users are ever modifying the file raw they're going to bork the tab characters -

The advantage you mentioned is the one I've seen that has the most benefit. If users are ever modifying the file raw they're going to bork the tab characters - nevermind some developer opening the file who has his editor configured to aggressively convert tabs to spaces. Tabs are trivial to actually type (so they're much off than, say, FormFeed) but they're difficult to visually distinguish. I also think it's generally a good habit to just force quoting of all fields in CSV to dodge any impending user errors. Human readable file formats have surrendered space efficiency for legibility and the main attribute they need to focus on, IMO, is defense against human errors.