I doubt the iPhone uses this, but don't kid yourself, it has the ability to monitor everything you do on that phone.
From a practical standpoint, manufacturers and service providers want that ability. But it's how they intend to use the information that counts. Nobody has proven to me so far that it's entirely benign.
When you say "it has the ability to monitor everything", do you mean that it would be entirely possible for Apple to build something into their phones to do this if they chose, or that they have already done it?
The first one of those is clearly true - Apple has control over hardware and software and could put pretty much anything they wanted in there to track your activity.
The second one is, to my knowledge, pure speculation. Apart from their anonymous stats - that you are able to opt out of - I've seen nothing to suggest that anything similar to this on iPhone.
You asked for proof that the data is correctly and securely used. That is what cannot be proved, regardless of your trust in the company or lack thereof.
From a practical standpoint, manufacturers and service providers want that ability. But it's how they intend to use the information that counts. Nobody has proven to me so far that it's entirely benign.