Board game in words by letters on a chess field.

Scrabbl and poker game - the reasons of popularity.

It is possible to talk about game in words or letters: http://www.wordgame.64g.ru/en.htm

Players have playing cards with alphabeic letters on a chess board according to rules of this game, and players move letters as a chess and as a result letters form words, that differs from the widespread board game "scrabble" in which letters only spread on a game board.

I offer an interesting question on popularity of game "scrabble" though in the world there are many other more interesting board games in words and letters.
And also the question on popularity of game in poker or popularity of gambling in preference.
Why poker is so popular in the world?