Would you want to wait 10 minutes for the player to be ready before playing a file ?
Well the answer is NO.
When a disk is inserted in to most players , they start indexing. A process where they go thru each and every file in each and every folder and read the ID3 tags in them like album artist genre etc. This is time consuming and prevents the users from playing music right after inserting the disk. If a player tries to do this in the background it will interfere with the player trying to read the disk to play the file. You will have two processes contending for the disk access, the player to play the file, the Indexer which is making the disk read each and every file. The caching mechanism in the OS is useless for the indexer since it reads one file only once so the OS needs to keep dumping its cache. This is the reason you will see the Drives continually run during the indexing process.
We made a clear decision not to index the tags for USB disks, so when you insert the disk you can play files on them instantly. Only once process access the disk and that is the player. We assume most disks users insert will already have well organized folders that they are familiar with. We would still display the tags when the song is played, just not when the disk is inserted. This saves so much time and frustration when playing files from the USB disks.