Yes, it is useful but it all depends of what do you want to achieve.
Policing is normally used to drop or mark down with another value the excess of the traffic. However, to limit to a subrate bandwidth, shaping is most commonly used as it buffers the excess, delaying the traffic, rather than dropping or remarking.
For example, policing is commonly used inside a class, typically to drop Voice traffic or transmit/remark data classes.
Hope this helps,
Jose.
