Yeah I avoided this technique (cloud backups) for the reason cited by nc_killie
: uploading your backups could take days or weeks. I actually ran into some articles that did the math and to get a handful of TB at typical broadband speeds could take months
(delays, throttling at either end, etc.). Downloading masses of data may only be marginally faster.
Remember that many of the cloud backup services tier their bandwidth, so unless you pay alot, they will limit your download speed.
Others, for a fee, will simply load your backups to a hard drive and send that to you instead (and let you start your backup the same way). Not cheap, but alot faster in the grand scheme of things.
I went with the "redundant offsite backup" technique. Every quarter I bring my backup drives home from their offsite location, mirror the drives I have locally, then take the backup off-site again.
This can be as inexpensive as small stackable/portable hard drives (did that for more than a decade) or as thorough and my current setup (two identical 16 TB Synology boxes).
My setup is overkill for just
photos; it's my entire digital life (computer backups, tax records, applications, bookkeeping, etc.); I looked at is as "future proofing my infrastructure to support my life and hobbies."