This will completely change the playing field as far as those unexpected "after charges" are concerned, whether by car hire firms or hotels trying to rip you off on the mini-bar. Not only will you be able to reclaim the unfair part of the charge, you could end up with the entire bill refunded. If you hire a car and the total cost is 450 Euros, then they later add a ridiculous 50 Euro charge for "tyre damage" or some such, after 1 November you can reclaim 500 Euros - not 50.
About time, as this has been going on for too long. It might make some of these people think twice. You will claim from Visa, etc., and in turn, Visa will simply deduct it from the merchant's transfer balance, whether they like it or not.
Andy