Earlier quoted context omitted.
Cloud storage is convenient, as one can then access it from any device. It's great to use as a temporary backup when traveling. But not as a backup strategy.
Why not as a backup strategy? I had my desktop harddrive fail and while I had some local backups but the cloud backup restored me to almost the minute of the failure. The only downside to cloud backup is the slow restore process.
Data theft is another one. Encryption might help, but you have no reasonable way of knowing if the encryption is secure.