Why is bishop slightly better than a knight? While i was going through the chess piece values, Bishops is worth 3.30 points while Knight has 3.0 points. 


  Although the 1/3/3/5/9 system of point totals is the most commonly
  given, many other systems of valuing pieces have been proposed.
  Several systems give the bishop slightly more value than the knight. A
  bishop is usually slightly more powerful than a knight, but not always
  – it depends on the position (Evans 1958:77,80), (Mayer 1997:7). A
  chess-playing program was given the value of 3 for the knight and 3.4
  for the bishop (Mayer 1997:5)
  https://en.wikipedia.org/wiki/Chess_piece_relative_value.


Please explain why is a bishop slightly better than a knight? I know it depends on the position for like as bishops, a knight can also have high points if it is placed on outpost.
Here are the reasons:


Bishops are stronger than knights in open positions, and open positions are more likely than closed ones. If you think of the endgame in particular, many pawns have been exchanged, i.e. many end games are open, favouring the Bishop
The Bishop pair is an advantage, as the light square bishop covers the squares the dark square bishop doesn't and vice-versa. So 2 bishops together compliment each other, but the 2 Knights do not. They actually replicate each other, potentially making one of the Knights rather redundant
In an endgame, a Bishop can cover both the Kingside and Queenside because it is a long distance operator, meaning it can perform offensive and defensive duties at the same time (e.g. help push a friendly passed pawn and stop an enemy passed pawn at the same time in a race). The Knight cannot do the same