Putting aside the marketing of "Must Have" (after all, haven't Microsoft been aiming for a new Xbox Live game every week for some time now?), Need For Speed is a strong brand name that has a lot of recognition in gaming circles. Admittedly this title does feel a bit of a dinosaur already (it's the 16th title in the broad franchise and was first released for the home consoles in November 2010), but it's another notch of recognition for Windows Phone.
I doubt this NFS will attract anyone to the platform specifically for Hot Pursuit, but having names like EA and Need for Speed promoted heavily will be noted. In the same way the hipsters and Valley geekerati are looking for specific third party web services to have Windows Phone apps, gamers are looking for dog whistle titles.
Building on that confidence is s more what "Must Have" is about that "look, it's another game."
Anyway, Need for Speed Hot Pursuit. In Xbox Live. Now.