That makes no sense. If you have backups locally, why store them on the cloud?
I didn't lose anything I've yet noticed. Very happy with how well the backup strategy held up, although potentially quite lucky the second on-site backup was unaffected. Didn't have to dip into the complexities of the off-site chaos (which reminds me...).
Geographical separation is important if you're serious.
However, I'm guessing that--if you're anything like me--you get lazy about refreshing it and, if something happens, you realize it's been a year since you did a fresh backup.
A cloud provider backup (as opposed to sync) is a good belt-and-suspenders cheap insurance backstop to local backups that you hopefully never need.
I have local Time Machine and Synology NAS but I also pay Backblaze a nominal amount. Companies were paying Iron Mountain large sums of money before there was a cloud.
Though online backups have their own risks (ransomware).
The probability that your house will be on fire these days is low, and the probability that your computer/hard drive will get on fire is also low (since you will probably take it out, no one will leave his phone in a burning house right?).
We can say that the probability above is that low that it doesn't really affect anything. There are many other different parameters to add, and I use a bit of math here which doesn't always reflect on life, but you get the point.