They do list in features:

> Coming soon. An integrated backup system provides a true "moment-in-time" snapshot backup of the entire distributed database stored to a remote file system on a schedule.

Snapshops / backups with MVCC isn't that complicated - you take a snapshot of the versions, and then backup the data at that version.

It is not complex, but it is very burdensome, usually because various garbage collection processes cannot act as long as the long snapshot is open.

Unless it locks when backing up or copying?

Yes. But then the data is not available or other transactions will fail to commit during a long backup operation, and most people don't like that.