I would; sync is no substitute for backup. Any data corruption or deletion propagates automatically via sync; whilst there are scenarios where sync will get your data back (a defunct device replaced by a new one, for example), there are many more where it won’t. Sync also does not offer versioning, so intentional or unintended changes to files cannot be reversed.
Backup is a must if you value your data at all. I posted my strategy in this thread on the topic.