Convenience is the enemy of security. Security is the enemy of convenience. You have to find where in the spectrum you sit to balance things out.

Personally, I work in computer security, networking, proramming, etc. so quite predictably I sit on the high security/low convenience end. What might be considered inconvenient to some, is normal everyday to me. But that is not to say that the way I do things is the right way for everyone. Online encrypted storage through a third party provider is miles ahead of no backups at all.

With online storage, you are at the mercy of having a working internet connection to access your data. Access is not a given in a disaster situation. But if your data is not time-critical for you to access, online storage may be just fine for you. And if the data you store is not really all that important, storing/encrypting to keep 99% of the hackers out may be a perfectly fine tradeoff too. "Tradeoff" meaning, dropping down to 99% security adds much convenience for you, in that you WILL backup your data at this level of convenience, but you probably would NOT go to the inconvenience of handling things at the 99.99% security level.

For most people, 99% security/accessibility (I just made that number up as an example) is perfectly adequate. The biggest issue I see for most people, is the questionable internet access that may keep them from accessing their data during a disaster. The chance of a company going out of business and you losing access to your online stored data forever is probably an acceptable risk for the vast majority of folks. That risk is certainly better than not backing up your data at all.