Sure it does when the search also investigates the contents of the files.
For example, GMail and Outlook do this for mail items -- you don't need to know the subject, which is comparable to the file name, to retrieve an email -- and Google Desktop Search (discontinued) or Copernic does this for file systems. It is almost as if every system-retrievable item inside a file (e.g. every word in a text document) automatically becomes a searchable item of the file.
The Outlook is a prime example for situation when pure search doesn't help. When I'm looking for some mail 1+ year old I sometimes don't even remember one correct word in it. Then I resort to some kind of tag system - folders, timestamps etc. And some times I don't find it at all.
For example, GMail and Outlook do this for mail items -- you don't need to know the subject, which is comparable to the file name, to retrieve an email -- and Google Desktop Search (discontinued) or Copernic does this for file systems. It is almost as if every system-retrievable item inside a file (e.g. every word in a text document) automatically becomes a searchable item of the file.