Visa and MasterCard threw their substantial muscle behind Google’s Host Card Emulation (HCE) feature this week in a development that has attracted a fair amount of attention. Mobile Commerce Daily questioned whether Google Wallet had outplayed the carrier-backed ISIS system, Droid Life called the moves a major win for Google, and Business Insider opined that carrier-backed wallets had suffered a major blow.

HCE, you may recall, was introduced last fall with the roll-out of Kit Kat as a counter-measure to the efforts of Verizon and other carriers who had blocked Google Wallet. Verizon said it did so because Google’s NFC-based payment system needed to access the phone’s Secure Element to conduct transactions; HCE circumvents the Secure Element by storing payment information in the cloud.

So, yes, Google has certainly found a way to prevent (at least temporarily) carriers from barring its Wallet app, and the backing of Visa and MasterCard is noteworthy. But ISIS remains a minor player in a mobile payments market that has yet to gain any substantial traction in the U.S., so it’s not like Google has suddenly stopped a runaway train. And a lack of carrier support is far from the only thing holding Google Wallet back — it is available only on NFC-enabled handsets (read: not the iPhone), it is far from ubiquitous at U.S. retailers, and it suffers from a huge lack of consumer awareness. Google certainly has some powerful weapons in an ultra-competitive market, but the company has much work to do if it is to come out a winner.