[0rzech]

Checksums are slow on HDDs and using SSDs for backups is a bad idea, particularly for cold backups, due to data longevity and the tendency for SSDs to experience sudden total failures instead of gradual degradation.

[Aachen]

The -c makes it do more reads, though, not unnecessary writes

Degradation won't get worse except when a file changed without metadata having been modified, but then that's exactly what you want

[0rzech]

Yes, but it's orthogonal to my comment.