Was Super Smash Bros a system seller for the Wii U like MK8 was?

[forethought14]

Mario Kart is more popular than Smash Bros. Also, the fans of Smash Bros likely already have a Wii U, since much of them also seem to like Mario Kart. However, MK appeals to a larger audience that eclipses Smash Bros' audience, it makes sense that it's more of a system seller.