Wanting a good camera on a phone means doesn't mean you just care about the camera, not exactly practical carrying two devices or having to transfer a photo just to upload it to instagram or whatever.
Pretty much this. Not only do you need to charge two devices all the time if you may need the camera, you also need to carry them both around as well. (You also need to worry about loss/destruction of one or both devices)
I don't know about you, but I typically carry Keys, Wallet, Travelcard and Mobile in my pockets and they're full from that already. Carrying an extra device is often impractical. So having a device you do carry around with you (mobile) that also has a Camera capability that does really well (especially in terms of what we've seen so far in what it can do), and it's going to be miles better to just look after the one device.
Although if we take Spit's post literally, then if you REALLY ARE just after a good imaging device, the Camera does beat the mobile (easily), no doubts there.