Useful? Let's put it this way: if you wanted to build a disc the size of the universe, to a precision of one atom, 50 digits of pi would be more than sufficien

Useful? Let's put it this way: if you wanted to build a disc the size of the universe, to a precision of one atom, 50 digits of pi would be more than sufficient. But, as Benjamin Franklin was wont to ask, what's the use of a newborn baby?