I partially agree with the author about puzzles being a waste of time for all cases except crosswords (or other word puzzles).

Part of me thinks that Sudoku is popular partially because people associate it with math - I do a lot of math in my daily work, and people thus assume I'm some sort of Sudoku guru. And this is obviously true, because Sudoku has numbers (nevermind that it would be exactly the same if it used letters, or animal pictures, or colors). In that case, I think it's a timewaster.

Crosswords are different though - you need at least a moderately-sized vocabulary, some historical and pop culture literacy, and a smattering of trivia to complete them, and what you can't complete you learn from, adding to that. Seeing the solution to a Sudoku puzzle doesn't make you more apt with numbers, but a crossword puzzle is definately better than a "word of the day" calendar.