Though I agree with the lack of security offered by a signature, that method of payment is basically offered everywhere in the US. Compared to Canada its uncommon to be asked for a 5 dollar minimum purchase or a 50 cent surcharge for a credit card transaction. Furthermore, the credit limits in Canada seemed downright restrictive.
Say whatever about the security of credit cards in the US but as a consumer the product is much more compelling. I can go almost anywhere, rarely pay extra fees and easily spend all of my own money. Furthermore, why would I care about a signature? Yes its antiquated but who cares if its never used, I can charge back fraudulent charges pain free in the US which has not been my experience in Canada.
Basically, I think the user experience of paying money is really important, but chip and pin doesn't solve that problem.