This is a tool of many uses.
In preparing the walls it is ideal for applying filler or caulk to long cracks in walls and filling holes in between lining paper that you left prior to painting.
It can be used to carry small amounts of filler or caulk to the wall.
Double cutting wall paper in a straight line is greatly improved with the use of the stiff straight edge of the blade.
It can be used give an edge up to which to cut with a trimming knife aling skirting boards, ceilings and architraves.
Sometimes know as a vinyl smoothing knife it can be pulled down finishing vinyl paper to smooth it down and remove air bubbles.