Typically this is because it is a good quality but for a great price.
Install vinyl drywall corners.
Luckily for homeowners installing corner beads and mudding them is one of the easier parts of the drywall process when you install corner beads apply light pressure on the bead itself toward the corner.
It is often referred to simply as bead because of the thin straight line that is created with the corner of the material.
Outside drywall corners have traditionally been protected with nail on metal corners but paper faced corner bead is simpler and resists cracks and chips better.
Drywall corner bead is made of either metal or vinyl and serves to protect the outside corners of walls.
All you need to install it are taping knives and a spray bottle filled with water.
Installed on the outside corners where two pieces of drywall meet corner beads create a smooth even seam and an attractive finish.