Most of the time, I use it to serve as a conditional for an IF statement. If
you don't tell the IF statement what to return if the condition you are
testing is false, it will return FALSE (a boolean value). I use "" as it
makes the spreadsheet look cleaner. If I have a lot of dependent
calculations that may not like "" and I don't care how clean the spreadsheet
looks, I'll have the IF statement return zero.