[Cretacerus]

The Choice Band set has actually always done a good job for me.
While it is true that he won't be able to sweep (unlike other variants), he can easily break down walls with his sheer power. This is especially useful for offensive teams, who commonly struggle against those treats.

There are lots of pokemon Rampardos can outspeed even without any boost, and if it ever manages to come out on one of those, you will almost certainly be able to severaly cripple your opponents strategie.
Sometimes you need a singe pokemon to fall, in order to sweep the rest, and this is what banded Rampardos is for.