It's not only about changing data with vi. Sometimes is about being able to recover critical data from a corrupt file with vi, rather than giving it up because the binary db file is f___ up, and someone forgot the change backup tapes for the last two months, and all you have is last night's backup of an already corrupt file.
Are you really sure a db will buy you something? Do you need ACID? Do you _really_ need an index to find your data? Be sure a database will buy you something before giving up reliability. For instance, have you thought that reading a 80 MB text file takes just a couple of seconds with any modern disk? That's a good million 80-byte records.