For instance, if you're looking to be shooting low-light action, over a variety of distances back-to-back (so, say, the 150mm f/2 might be less obvious of a pick), the f/2.8-3.5 might help over the slower values of either 40-150mm version.
The extra 50mm also helps if, say, you're shooting from fairly far away -- ex. shooting from stands, or any opposite-field or outfield shot for softball or baseball.
If you're going to be flying a lot and need the most compact, lightest travel zoom, and a fast aperture isn't a priority... well, this isn't the most obvious pick, as it weighs 2.4 pounds (with collar) ( ) and takes up some space, and you'd need something else to cover the wides for street/landscape photography.
( ) I tend to shoot without the collar attached. If I'm shooting softball, a monopod or the ball head on my tripod would just get in the way of rapid acquisition, as well as mobility, and I don't want the collar even possibly slowing down my use of the zoom ring. Collar goes back on if I'm using a 'pod, 'tho.