What are the advantages of tagging?
Some things require tags in order to work properly, such as the Last.fm
service. And some MP3 CD players (like mine) rely on tags to let you know what you are listening to, searching for songs, and allowing you to set up playlists.
Also, there is more than just artist/album/track/title that can go in a tag, such as genre, lyrics, year, composer, url of artist's homepage (or where you downloaded it from), original artist (if it is a cover tune), copyright holder (if it is different than the artist), comments (or a tiny bit of related trivia, or a list of all the members of a band).
You could never include all that info in the file name...it would be much too long.
People that are true music freaks will research all this stuff and add the info to every track they have. Then they will never wonder about it later because it's all in the tags in case they can't remember...or if they have software that can utilize the tags they have added. It is particularly useful with software that allows you to search your collection and gives results based on tag info.
So let's say for example you want to make a play list of all songs by and related to John Lennon and you do a search of your collection (provided you have an application or player that supports all tags and your files are fully tagged with all data).
You would get as your results...
- all songs by him specifically
- all Beatles songs if you put his name as a band member in the comments
- all songs that are covers of his songs by other artists
- all songs that mention his name in the lyrics
- all songs he wrote the lyrics for but never performed himself
- all songs he composed the music for but maybe didn't perform
- all Julian Lennon songs if you added that he was the son of John Lennon in the comments tag
- all Yoko Ono songs if you added that she was his wife in the comments tag
- etc, etc, etc.