An online or cloud-backup scheme has many real benefits, especially if -
(1) your data can be safely encrypted before you upload it, and
(2) if your backup servers are in your own country rather than on some "overseas" servers.
(If your business depends on you having access to your files under all circumstances, then that last point is an extra big comfort. I leave you to consider the complications over any disputes or backup-company take-overs etc., if you're working across national borders.)
But in my own real-life experience, the biggest flaw with large online backups is when the time comes to retrieve your data. It's lovely to watch our files pour slowly "up" onto safe and sound off-site servers each day, but any restore operation will take literally days of download time before we recover an entire multi-gigabyte backup. Not to mention the hands-on time needed to select files to recover, and to oversee the downloads, and then (if we're wise), to run some verification process afterwards ...
Some online backup schemes (such a Amazon S3) can send our full "recovery" backups to us overnight (or almost overnight) when necessary, in courier-delivered physical hard drives, which solves most of those recovery-delay problems - but at extra cost of course.
I admit I'm repeating stuff that's been aired in these forums many times before ... but - depending on the absolute "value" we'd place on our images if they should ever be lost en mass - perhaps an ideal backup scheme would be a combination of all of the following -
(a) cloud-based backups - for assured-but-slow recovery of any file or small sub-sets of files, and
(b) a pair or ideally three "local" hard drives, rotated as frequently as is feasible to somewhere off-site, and
(c) a quick and roomy ON-site server or a networked storage 'box', to which we can make rapid initial backups, and to give us speedy access to (possibly) our entire library.
You'll hear many people say that having just two copies of our data is to have "one copy too few", and I strongly agree with that! I've watched a grown man weep when his "second backup" turned out to be not quite what he thought it was ...