Without a doubt. After being stung to the tune of £3k on a TFSI A3, I would never run a car without it (and haven't since). I understand people have a slush fund but they soon whittle away if multiple unrelated issues occur in quick succession.
In my view it goes beyond repair work, and take into account how much easier it makes life in the event of a breakdown instead of an engine management light scenario. The fusebox went on my JCW in the middle of Cambridge. The car was recovered and taken to the dealership I requested along with a Taxi that dropped me home and a courtesy car was delivered the following day; that alone would have costed a few hundred and that's all ahead of the car being looked at.