Why are there several Importers; do I need to run them all?

Sapphire has several importing methods.

• Populate File Data – Tells Sapphire to examine all files, and remember the file size, length and other information that can be gathered from the file itself.
• Fetch TV Show Data – Tells Sapphire that for every TV episode, gather more information about this episode from the internet.
• Fetch Movie Data – Tells Sapphire that for every Movie, gather more information about it from the internet.
• Import All Data – Tell Sapphire to do all of the above importers at once.