Comment by thayne

> you still have the same amount of data to back up no matter what

But you can restore/back up the databases in parallel.

> If you need to backup/restore just one set of tables, you can do that with a single DB server without taking the rest offline.

I'm not aware of a good way to restore just a few tables from a full db backup. At least that doesn't require copying over all the data (because the backup is stored over the network, not on a local disk). And that may be desirable to recover from say a bug corrupting or deleting a customer's data.