Why cloud saving matters
Both Steam and iOS have a platform for cloud saves, meaning that the developer can build hooks into their game that put their save games into the cloud (Steam Cloud and iCloud respectively).
Beyond the obvious feature of not losing saves and syncing them between computers, this has one huge benefit; it means that when I install a game, like XCOM:Enemy Unknown on iOS or Portal 2 on Steam, I don't need to worry about the kind of space it takes up. The Mac version of XCOM takes up 22GB. The Mac version of Bioshock Infinite with the current payload of DLC comes to about 27GB. It just takes a handful of these games to make a real dent in my busy laptop's 380GB mac partition. Likewise, the iOS version of XCOM comes in at a not-inconsiderable 1.8 GB, which is a big chunk out of my 32GB iPad's storage. I've installed and erased these games over and over because when I'm working in a video or photo project, I desperately need the space at short notice (a recent three day project ate over 200GB on my laptop!). It's great to have the freedom to do that without worrying about my saved progress.
The real knock on effect comes when I'm making the decision to buy or install games on my devices. I played Deus Ex: The Fall on my iPad recently. They plan to release new chapters that carry on your choices and character from previous games, but I realised with a sinking feeling upon finishing it that I wouldn't be able to uninstall Deus Ex: The Fall any time soon, or I'd lose all of my progress. That game is sitting inert on my iPad. It's a story-based game so I don't see the point in replaying it, but I also don't want to lose my place in the story! This oversight has left me leery of making similar mistakes in the future. Every time I am tight for space and have to delete something more accommodating or less essential, I resent the oversight a little more. Sadly, also on the shitlist is Knights of The Old Republic for iOS, a brilliant game that I now regret buying; I've replayed the first twenty minutes about fifteen times now, I'm getting too sick of it to think of fighting past it yet again.
A more flexible alternative is the use of a more open platform like Dropbox. Being able to control, archive and view my saves is ideal, but I've only seen it once or twice.
I'm sure most developers have thought about this issue, but cloud saving is not as ubiquitous a feature as I'd have expected. I hope it becomes standard in time.