It's actually kind of a milestone and I sort of expected it. I tend to have high expectations of him. When I first saw the flub with the oath of office I kind of remembered and kind of expected that Roberts was the one to screw it up rather than Obama, because Obama wouldn't make such a silly mistake.
Apparently this nation includes non-believers. It's a small gesture, but you kind of hate to be left out of inclusive language. Hooray!