It does other things than just fold/unfold the mirrors, although that does seem to be more than I paid for mine. That said, I have had the Autowindows module fitted for the last 4 years now.
Its funny when you jump out the car with the window down, zap it to lock and walk away - anyone passing will always say "your window's open mate" then they shut up as the mirrors fold, then the windows close
I thought the motors were packing up on mine as they were making a hell of a racket when folding. Turned out there were some tiny bits of grit inbetween the mirror cover and the base plate of the car, basically in the hinge area. Cleaned them out and they've been quiet(er) ever since