What is the purpose of the thin backing sheets behind the brake pads on almost all cars?

If it is to allow the pads to slide around, why do we put permatex on them to hold them in place and stop noise?

Just wondering if anyone just drops in the pads with nothing else.

 

i do.

three different sets of pads have had those metal pieces work loose and cut into the rotor.

the anti rattle hardware is more important, in my expereince.

 

Im wondering if its part of the manufacturing process more than something thats needed for the performance.

 

i belive it is to minimze noise and give even pressure on the pads. wether it works 100% or not is another thing.