Online storage backup is totally impracticable for most HOME users.
1) Upload speeds of typical HOME (not WORK) ISP's are usually pretty abominable.
2) some users CAP bandwidth which renders this stuff totally impracticable.
3) If you take a typical users data these days - especially with Photos, MUSIC (particularly) and other data - maybe video as well this could even run to several hundred GB or even a few TB. (1TB = 1000GB for those not quite sure - and a lot of ISP's cap stuff to around 50 GB a month).
Uploading this stuff via a home ISP would probably take longer than the remaining estimated lifetime of our Sun -- around another 4 billion years
. Even downloading on a fast ISP would take a while.
4) You might not be online when you need your data.
5) the Online service might be unavailable or gone bust.
6) Your Bank data has just been sold for 5 USD in a back street bazaar in Bangalore or similar.
With CHEEEEEEEEEEP usb drives just backup stuff at home and have done with it.
For really important data keep another set and store them in another location.