Storing an unencrypted file with a single storage provider is neither private nor secure. Blockstack allows users to select multiple storage providers, allowing for data replication and mitigation of any single source of failure. Additionally, encrypting a file client-side before it is stored means that Google or Dropbox or whoever can snoop all they want and not be able to see your data.
If it's stored on Dropbox, why not use any local editor?