What is the point in backing up iPhone if you are using iCloud?

So I don't see the point to select the "backup device to iCloud" (settings>icloud>storage and backup>icloud backup ) in the iCloud settings menu. Nor do I see a point to back up to iTunes (wi-fi or USB) if you are already synching data to iCloud.

So pretend you loose your iPhone, buy a new phone, and re-sync it to your iCloud account.

iCloud syncs photos, bookmarks, notes, calendar, contacts, and documents. As far as itunes purchases, they are always on iTunes to be downloaded, at will, under my itunes account. Any CD's that I rip to iTunes are on my mac's hard drive, and can put them back on the phone with a quick sync.

So please explain to me why I need to "backup my iPhone" to iCloud.

I understand why "syncing" with icloud is good. But why turn the iphone "storage and backup" slider on? (settings>icloud>storage and backup>icloud backup on.) Can someone please give me one reason that I would want to use this option?

The only thing that I can think of is the phone's settings would return to default? And maybe so that Apple can sell you data that you don't "really need".

Am I wrong on my assessment about this?

I was wondering about this too but when my itouch (works the same as iphone) got stuck in recovery mode and wasn't recognized by itunes I had to bring it down to apple to restore. Well I have most my music burned from cd's so ya I just re synced but it saved me alot of time because I didn't have to re-enter all my contacts and info and didn't have to worry about losing my notes (which I use to put stuff down I Absolutely HAVE to remember at work and I tend not to so it probably saved me from losing my job because its what you HAVE TO DO and i'm new to it so I still don't remember all of it so I'm constantly pulling out my itouch to read notes. So basically you may still see no purpose but if something happens you may be very very happy you did turn it on. I would recommend it because you just never know what might happen.

A secondary backup is standard practice. What happens if iCloud is not available or horrors of horrors, your data is lost or corrupted in iCloud, then what do you do?