I think the point is to elevate Siri to celebrity status, to make sure everyone knows what (who) she is. But I think they play more like run-of-the-mill celebrity ads — more like just, Hey, Sam Jackson has an iPhone.
These ads were at first speculated to be made by Verizon, but they weren’t. You should probably read ad executive — Bob Hoffman’s — 5 signs Apple might be losing it, in which he astutely points out to advertising practices that may display a distracted Apple in the future. These ads to me seem like gimmicks and unnecessary. Also, Apple has heavily relied on Siri to market the 4S. It’s as though Siri is 4S’s primary feature. It is not. Certainly a “beta” product can’t be Apple’s primary subject for it’s advertising campaign. I personally feel Apple should let go of the “beta” tag. Unlike Google’s beta products, Siri at least works.