As with everything in ARCHICAD, there are several ways (or seemingly infinite ways in some cases) to model any design conditions. When it comes to a wall end wrapped with a finish or trim, there are only a couple of good options. 1) The wall end tool, and 2) a custom profiled column.
Option 1 falls apart in several conditions and for one specific reason. In floor plan, the wall end has lines that you may not want to see, and in RCP (3d Document) the fills and pens do not match. The reason for this is that the walls use building materials, but the wall end tool is a GDL object which uses fills, not building materials. A fill will never clean up with a building material, so option 1 should be considered an unacceptable solution.
Option 2 has the advantage of using a building material, cleaning up perfectly with the wall and looking correct in all views. Additionally this option forces the wall length to be modeled correctly to the actual core length, as opposed to the full wall length (face of finish) that is required for the wall end tool to show correctly. The only shortcoming a complex profiled column has is the column does not move with the wall when the wall is extended or shifted; but its a small amount of coordination to ensure the plans, elevations, model, and RCP all show cleanly and correctly.