It's mainly fine scratches that you can normally buff out with polish which you can't do with matte otherwise you end up with a gloss section, and if you enjoy waxing your car then that will not be available either. I had a matte car a few years back and I really missed not being able to polish it and seeing that lovely gloss finish. Matte is also a lot harder to paint match if you ever need a repair. Personally after owning a matte car I wouldn't buy another one but on the positive side I expect Hyundai will charge extra for the matte finish on the configurable cars so those who have ordered Gravity gold will have a little bonus.What aspect of the gravity gold paint care are you concerned about?
edit: I did some research on matte paint and I think I see its shortcomings now.
Hyundai should have made it clearer on the configurator that Gravity Gold was matte I did see some reference to the paint being matte on some 3rd party websites but no mention when I placed the order for the 45.