It did care. See: https://github.com/boostorg/spirit/blob/master/include/boost/spirit/home/qi/numeric/real_policies.hpp#L42

Note: extract_uint<Attribute, 10, 1, -1>::call(first, last, attr_);

and similar in parse_frac_n and parse_exp_n.

But yes, you can "override" those with your own policies, if that's what you mean.