a quiz machine can be considered equivalent to any other pub game: darts, bar billiards, dominoes, skittles, pinball, karaoke... each offers simple enjoyment to accompany a glass of what you fancy.
if you find yourself in disappointing company but you want to carry on boozing, you can play a game. the pub is established as part of this great nation's culture, while the take from an SWP may not be enormous, it should also be considered that it increases money spent behind the bar and subsequent patronage. i'm not suggesting that people go to the pub just to play SWP but it is would be foolish to suggest that they were mutually exclusive.