That gives legibility a huge jump. Lange started applying ARC on their glass relatively recently and the early production of Lange did not have it. I loved it when I replaced the Lange 1 MOP and the mysterious varying light and color on MOP dial became really beautiful. There may be the time when ARC glass actually hurt the beauty of the dial, but I can't think of any for the momet. I used to wear glasses on and when I changed my glasses to the one with ARC, the difference was night and day, so it must be good for watches when it comes to legibility.
Ken