Several reasons: It's to cover the gap between the floors and the walls. So, floors are made of wood, so expand and contract with heat. If the walls were butted against them, they would be damaged when the floors expanded; and a gap when it contracted.
They enable easier access and routes for cables and power points. You can get to thing by removing the boards, rather than damaging plasterwork and the finishing over that. They are decorative, in the same way as you put a frame around a picture.
It also covers up the un-even plasterwork at the 'ends' of a wall, which is difficult to manage. Just like we use coving at the top of a wall at times. Although this isn't as necessary, as floors move more than ceilings, cos we walk on floors, and bounce heavy objects on them.
More.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.