It is primarily used to give cover to the original seats and protection to car's seats from spills and dust.
Seat Covers are installed over the above of original (company fitted) covers of the seats. By this the life of original covers got increased.
High density foam padding is being used in it,for comfort and durability.
These are sticthed very precisely to fit on the seats perfectly (a.k.a. bucket fitting).
These are easy to clean and maintain - you can just wipe it with a wet cloth.