I know that Matlab is essentially a giant numerical analysis package, so numerical analysis is helpful for anything that involves Matlab or FORTRAN or non-symbolic programming languages (or processes that use approximations of differential equations and stuff). So pretty much anything with giant data analysis requires some numerical analysis (atmospheric science, physical oceanography, physical science, astrophysics, etc). I've always had the feeling that theoretical physicists and mathematicians disdained numerical analysis. Maybe it isn't useful for them. But for the rest of us, is it possibly more useful than perhaps any other field of math/physics?