Like a lifting belt, usually not needed for BB'ing.
Wraps are a staple for PL'ers, when going for a max effort or 2 to 4 reps in heavier training. Some will even wrap the ankles and of course elbows. Quite a few even use wraps as a precaution (or habit) against strains/injury even though the joints may be in a good and healthy state. Becoming too dependent on wraps may be a mistake during a training career. Though wraps can give a sense of security in any lift. Perhaps false , at times, because injury's can still happen. Depending too much on wraps may actually weaken the knees for some.
Wraps must be placed correctly and fit very tight for a shorter range of reps, between max to 2 or 3. This can be one reason BB'ers may find wraps limiting in a normal higher rep BB'ing workout. If you do have knee/ankle problems, as a BB'er, than feel free to use wraps, they can offer support.Though the tightness may have to be adjusted to your needs. This can also be said about using a lifting belt in a BB'ing workout.
Keeping the area warm with knee/leg warmers for example, might be a better idea, than using wraps, if the knees are in good respectable condition.. Using, before and after leg training, a warming element like a lotion, cream, heating patch, etc, which brings blood to an area, may also help to keep the BB'ers knees to remain in a healthy state. Good Luck.