High performance fire rated systems are often used in corridors, along escape routes, staircases, common areas and high traffic areas for example. This is to ensure the safest possible evacuation from the building, and ease of entrance for fire fighters.
It is also important to consider that different locations will have different safety requirements. For example, Approved Document B Volume 1 refers to dwellings, whereas volume 2 refers to commercial buildings and more. You can read Document B here.