It doesn't. I've had it done on 3 cars with no issues. Sold one car and faced no issue with it, 2nd and 3rd car still with us and no issues so far. One is now about 4 years in and the other one about 1.5 years in.
It's a myth that the windscreen will scratch up quick after the buffing, obviously have to use good quality wipers. Besides you've got nothing to lose spend around 5k and experience it for yourself, if it doesn't work out you can always get a new one 