I use the back protector for snowboarding and for this is super useful. It is best to wear under the jacket, this does not interfere with the protector and further does not stand out from the outside. Falls begins the protector from good and one is also not limited by the type of movement.
However, one should note that it is relatively warm at the back with the protector. The money, however, is well laid out and you can risk-free on a skiing holiday.