Technology seems to be getting closer and closer to a weird transition where things have become so convenient that users are getting lazy, but laziness can still cause huge problems down the road with a little bad luck. This is exactly the case when it comes to backing up data, a process that many people ignore completely because of what can only be described as ignorance. We may trust hardware companies to deliver quality products that can be relied upon, but the bottom line is that things go wrong. Backup hosting is there for when a hard drive crashes or a piece of software creates some kind of nightmare scenario.
The idea is to simply keep backups of important data in an independent location, which will hopefully prevent the loss of data in almost any scenario. Sure there are external hard drives and other options that people often use, but what happens when a building catches on fire or water damage takes out an entire room? The bottom line is that the safest way to protect data is to have multiple locations which provide redundancy in even the most extreme cases.