As long as we can buy exactly the amount of Arx we need for a purchase nothing changes but having to buy Arx before buying the cosmetic. I fear though that it will come in packages and that there will be leftover. I absolutely loathe that and was a reason for me to not buy anything anymore in other games.So its essentially a pre-pay system. Cash up front.
I'd like to see the current front store mechanic remain and ARX points be an addition, but not the only option.