Makes very little difference to me, it's not my money. But I can't see how the argument of 'it's ok to have it there, because the country was founded by christians, even if it's no longer an officially christian nation now. It's appropriate because the reason it's there is because of our heritage' holds any water. As others have said, it wasn't put there by christian founders, it wasn't put there as a nod to those christian founders, it was put there in a fit of jingoism to differentiate the U.S. from the godless commies. While there's still no shortage of jingoism, there's no reason to try and officially emphasise that 'we're not godless commies' anymore. McCarthy is no longer with us, even if his legacy is.
The real question is why aren't american notes of different denominations easier to differentiate? Australian pesos use plastic notes, with different colours for 5, 10, 20, 50, 100 peso notes. Each one is also slightly longer than the smaller denomination, to help the blind differentiate them too. AFAIK, the only difference in american notes is the number and the face printed on them. Same colour, same size, so you need to actually look, rather than being able to tell at a glance, how much it's worth. Why is that?
The real question is why aren't american notes of different denominations easier to differentiate? Australian pesos use plastic notes, with different colours for 5, 10, 20, 50, 100 peso notes. Each one is also slightly longer than the smaller denomination, to help the blind differentiate them too. AFAIK, the only difference in american notes is the number and the face printed on them. Same colour, same size, so you need to actually look, rather than being able to tell at a glance, how much it's worth. Why is that?