I am thinking that today's puzzle is incorrect. Black's move after white's supposedly correct move is sub optimal and causes him to lose the game. White smooth, my move, seems somewhat arbitrary. I don't understand the logicbehind what is considered the ideal move for white.
The puzzles should have the same first move, regardless of black's reply. Most of the time, the puzzle is showing a thematic idea and that is why a given defense is played. Even with best play, the first move should provide some advantage over other potential first moves.