Some people, like my parents, don't have a laptop / PC.
Anyone arguing that they want to use some of these more obscure cloud backup solutions almost certainly has a Mac or PC at home.
There is nothing wrong with wanting the same ease of use and integration that iCloud affords, but extended to other clouds. Requiring additional steps (back up to machine, then upload to cloud) are, technically, nonsense, and is simply Apple flexing its’ anti-competitive muscle.