Why exactly would someone want their iPhone back-up on the cloud? I'm serious, what are the advantages? Wouldn't this waste space on someone's iCloud account. This would use up over 25% of someone's iCloud account - for a file you would rarely even use. Seems to me this is just for sht n giggles and would be more practical to just keep your back-up on a local computer.
A lot of people, myself included, do not make the daily habit of connecting their iOS devices to their main computer and making sure that they back up their devices. The backup in iCloud thus provides a more up to date backup in the case that something happens and I need to restore it. It's nice that it backs up at least once a day, especially when I go to sleep and have it on charge and connected to Wi-Fi. Most of my backups are at night between midnight and 3am.