The government's arguments were weak at best and the court did a nice job of pointing that out.
Court says money discriminates against blind people - Yahoo! News: "The U.S. acknowledges the design hinders blind people but it argued that blind people have adapted. Some relied on store clerks to help them, some used credit cards and others folded certain corners to help distinguish between bills.
The court ruled 2-1 that such adaptations were insufficient. "The government might as well argue that, since handicapped people can crawl on all fours or ask for help from strangers, there's no need to make buildings wheelchair accessible*, the court said."