Why can we not get away from this myth that COD is a big title for Vita?
Regardless of quality, CoD Declassified has the most sales potential out of any currently announced Vita game (with the exception of maybe AC: Liberation). I think everyone would agree with that.
Same reason why they'd carry a smartphone and a 3DS or a smartphone and an iPad. Two devices serving two different functions. There are many who don't use their smartphones as a gaming device.
I don't think there's many people that actually do this. Research Finds That 62% of iPads Never Leave Home