Using a regular file system it is normal to have some conventions about where to store the files. Those conventions can be hard to maintain especially if there are a lot of users which uses the same directory (e.g. a network shared folder).
Using a metadata file system, it is only necessary to obey conventions about which metadata must be stated. This should be easier than using the directory structure. An other advantage (maybe the biggest) is that it is easier and faster to locate certain groups of files, compared to a regular file system, even though you know exactly where each of the files are located. The following example should illustrate this very well:
Suppose you are in a company (I will use products from IBM in the example) which have a lot of documents on there network share, and they are of course arranged nicely in a folder structure like this:
\Docs\PlayStation3\R&D\Electrical_engineering\Mainbord_def.txt \Docs\PlayStation3\R&D\Electrical_engineering\Sound_system.txt \Docs\PlayStation3\R&D\Mecanical_engineering\casing.txt \Docs\PlayStation3\R&D\Mecanical_engineering\ce-certificate.txt \Docs\PlayStation3\HR\Administration\Christmas_party.txt \Docs\PlayStation3\HR\Administration\payment.txt \Docs\Cell\R&D\Digital_Design\Super_fast_multiplier.txt \Docs\Cell\HR\Administration\Chrismas_party.txt
Suppose you would like to take a look at all the documents which have something to do with ``HR'', or ``R&D'' then you would have to go through several folders to collect all the files, in a metadata file system can you just state the metadata you are interested in. It would of course be possible to design another folder structure where this enquire would be easy to satisfy, but you can never satisfy all possible enquires in a regular file system.
An other example could be if you have all your personal digital photos on your computer, and you would like to look through all your Christmas pictures where your mother is on. If you are using a metadata file system, and have entered metadata about events, and name of the people on the picture, then it would be very easy to find.