You might've answered your own question, PAMetalBoss... one move longer could mean the difference in a blitz/bullet game, or even a regular slow play  match with time running out. The fewer the moves to checkmate, the safer and less chance for error, or even a mishandled piece.  The smother mate damages your opponent's ego and will more, yes, but not if he/she has 1 second left and you have none.  Then you'd just look like an idiot.

I thought it would be smothered mate.

Smothered mate doesn't work.

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