sparse with rsync issues 1KB w/r as opposed to 32KB r/w. XFS handles this a bit better than ZFS, but if you use the combination of the options on a FUSE mount (suchas mergerfs) you're in for a really bad time as throughput will plummet.
As such, dropping sparse results in a 31x reduction of context switches to copy the same amount of data, and more efficiently uses the disk.
https://github.com/trapexit/mergerfs/issues/902#issuecomment-830928020
sparse with rsync issues 1KB w/r as opposed to 32KB r/w. XFS handles this a bit better than ZFS, but if you use the combination of the options on a FUSE mount (suchas mergerfs) you're in for a really bad time as throughput will plummet.
As such, dropping sparse results in a 31x reduction of context switches to copy the same amount of data, and more efficiently uses the disk.