Works both ways. If you're too inept to operate a simple phone camera no amount of feature upgrades is going to help.
The point is that any camera is only as good as the photographer holding it. Take OIS for example. A lot of people, judging by the posts here, think of it as if it's a sharpening tool or a way to stop action in a shot. But it doesn't work like that. It gives you an artificially steady hand. Like putting your camera on a tripod. If you don't have a basic understanding of what a tool like that can do and how best to use it you're still going to get a dodgy result. HOWEVER, if you're like what I assume is a pretty large percentage of iPhone users and have an average or better than average grasp of how to use them these kinds of upgrades become very significant, because when used right things like OIS and phase detection pixels will get you the shot you wouldn't have gotten before. Whether it not that shot is any GOOD in terms of content and composition is all up to the photographer.
In short, the sharper, more color accurate, better focused picture you take with the "improved" camera is still going to suck if you don't know where, when and how to point that lens and click the shutter.
Or you miss the scene entirely because your camera phone just couldn't do it, but your pro-dslr with big old red-ring lens wouldn't have even sweated. It is what it is but a camera phone is better than no camera at all.