This is Apple ensuring the best possible experience for the customer.
I agree, Greg. This isn't the same as saying it will be a flawless product on the phone, but that it makes it easier to say "your carrier needs to fix this, because before we let them have this phone, they had to pass stringent tests. Our phone is matched to what they promised to provide. If you have the signal, you are supposed to have a pleasant experience." All handset makers should be this way.
Disclaimer: I do not have an iPhone, and have no plans; indeed, I updated my handset last July to an HTC Evo 4G LTE device, and my two iPads are WiFi only. I have no horse in this race, at this point.