A necessary part of any photographer is the polarizing filter. Thus, unwanted reflections on glass surfaces can be removed really excellent. Logically, the filter is rotatably mounted on the thread to find the best polarization setting. Filtering out certain polarization planes is also one of the few things that are no longer even with the best post-processing software in principle possible.
The use of UV filters is now already controversial. Most photographers use it simply as a protection for the lens of the - usually very expensive - lens.
The lens hood has been probably added especially for all Canon camera buyers to this set because it is missing in the standard kit.