I would rather make more use of the speedbrake than deploying flaps and slats to decelerate. For one thing, the slight vibrations it induces is more tolerable than a rapid change in pitch (ballooning effect) that flaps may induce in a descending aircraft. This is less pronounced in level flight. And Atlanta-Driver is right. Less stress on the screwjacks and flap motors.
Other aircraft types though have higher speed ratings for their flaps/slats, like the DC9. These planes could make use of their flaps as drag devices as these could be deployed at 280kts (Flaps5), 240kts(Flaps15) down to 210kts(flaps25) and 180kts(Flpas40/50).