Database as a file system. In some ways it actually makes an odd sort of sense...

    SELECT * FROM sdc
    WHERE Type='mp3';

I could see uses for something like that. You could even treat it like a traditional file system for fallback purposes, if one of the tags was a 'directory' tag.

Also, it would make sense in cases where you have... [whatever the equivalent for NUMA is for disks. NUDA? Things like hard drives with a limited flash cache.] Store the indexes on the flash or in RAM (periodically backed up to the disk, of course). Biggest issue would be wear on the flash, though.