Perhaps in the future when cloud drives are all 4TB+ in size, and our upstream connection speed is measured in gigabits per second, I'll be more comfortable with a primarily-cloud-based backup solution. Until then, I view the cloud as an additional element in my backup strategy, not a primary destination.
Although we have more than one Mac in the house, all of the key files reside on my primary iMac. The other machines have their data files backed up to our Time Capsule via Time Machine. Critical files are then copied out to a cloud drive on a regular basis (and encrypted first). However, I don't bother with a boot clone for the other Macs. If one of them were to have a disk failure, it'd be an inconvenience, but no single disk is so critical to us that it needs to be up and running immediately.
The final word
I'm probably an outlier in terms of backup strategy; I don't expect nor preach all to follow what I do. But you should have some kind of backup plan for your data, and that plan should involve redundant backups, with at least one of them being stored offsite.
You can accomplish this with Time Machine and an offsite backup, or Time Machine and a cloud service backup, or some other combination of here and there schemes. The important thing is to have copies of your data files in multiple places.
In addition, your backup plan must be as simple as possible to implement. If it's complicated, you won't keep up, and an old backup isn't much better than no backup. After years of trying various solutions, I'm incredibly happy with the amount of automation in my current plan. All I have to do is drop disks into a drive dock and CCC4 and some scripts do the work.
With any luck, you'll never put your multi-site, multi-copy backup system to use. But if you do, you'll be very glad you went through the trouble of creating a comprehensive backup plan!
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