The BSU is a unit (megabyte) in the inery, so the fees are paid in this unit. Inery is not a Google Drive or Dropbox solution. The basis is currently there to set up a database solution. Specifically, Inery is a decentralized virtual database solution on a blockchain. The future of Inery is based on IneryDB, which can be compared with central databases such as mongoDB etc.
Inery use the decentralize technology which is developing very quickly. I think that it is impossible to compare Inery with centralize storage.