Out of curiosity, why do you think so? I don't have experience with any other implementations of copy and paste on any other handsets, but it works great for what I do with it.
More so the fact that the interface gets in the way doing things that were fine before cut and paste came to the iPhone, combined with the fact that I have not had any desire to cut/paste on the iPhone - neither before nor after it was possible.
Originally going back to edit text further up in an email/note/text was very quick and painless - since cut and paste it always brings up the buttons and assumes I want to select a range, which is never the case, and of course there is no way to turn it off. Just like the equally annoying feature of apps like Mail and Safari rotating to landscape when there is no conceivable reason I would want them to and it just makes browsing while lying down more annoying. The iPad's rotation lock switch is a good sign, but I don't see it coming to the iPhone unless they can work out a combination with the silence switch.