On my home machines, Duplicati backs up to my NAS which uses btrfs.
I think snapshots are useful to protect your backup data from accidental or intentional damage (by ransomware for instance). My NAS automatically takes snapshots and deletes them after a certain time period.
Also I think its ability to detect and recover from “bitrot” is beneficial (Duplicati itself has no integrated ability to heal from such errors, although some initial effort was made to implement it.)
Its other filesystem features are probably of little value to Duplicati, but they don’t hurt anything.